In the late nineteenth and early twentieth centuries, automobiles were commonly referred to as horseless carriages after the older technology...

Let's begin by understanding the meaning of this sentence. We'll use our understanding of pause points and segment the sentence as shown - understanding and assimilating the meaning of each segment bit by bit!

Sentence Structure

Sentence 1:

• In the late nineteenth and early twentieth centuries,
• automobiles
  • were commonly referred to as horseless carriages
    • after the older technology
      • they still resembled.

Sentence 2:

• Known as the Brass Era,
• this period in automotive design
  • is remembered for its grandeur and artistry,
  • its vehicles [?] highly prized by collectors
    • for their ornate detailing and gleaming brass fittings.

Understanding the Meaning

The first sentence gives us historical context:

• In the late nineteenth and early twentieth centuries,
• automobiles were commonly referred to as horseless carriages
  • after the older technology they still resembled.

So we're learning that early cars were called 'horseless carriages' because they looked like carriages but without horses.

Now the second sentence:

• Known as the Brass Era,
  • This is describing what comes next
• this period in automotive design
  • The subject - referring back to that time period
• is remembered for its grandeur and artistry,
  • Here's the main action - telling us what this period is known for

Now we have a comma, and then:

• its vehicles ______ by collectors for their ornate detailing and gleaming brass fittings.

This is where we have the blank. Let's look at the choices:

• A: are highly prized
• B: had been highly prized
• C: highly prized
• D: were highly prized

To see what works here, let's understand the complete structure of what we're reading!

What do we notice about the structure?

The main part of the sentence is already complete:

• 'this period in automotive design is remembered for its grandeur and artistry'
  • Subject: this period
  • Verb: is remembered
  • This is a complete thought

After the comma, we have additional descriptive information:

• 'its vehicles ______ by collectors for their ornate detailing and gleaming brass fittings'

Now here's the key question: Is this additional information a NEW complete sentence, or is it extra descriptive detail about the period?

It's providing extra descriptive detail! The sentence is fundamentally about the period being remembered, and this phrase adds more information about the vehicles from that period.

If we used a complete verb (are/were/had been highly prized), we would create:

• Complete sentence + comma + complete sentence
• That's a comma splice - a grammatical error

Instead, we need a structure that makes this descriptive, not a new complete thought:

• We need the participial form 'highly prized' (without a helping verb like are/were/had been)

This creates a pattern like:

• Complete thought, [noun + descriptive modifier]
• 'the period is remembered..., its vehicles highly prized...'

Similar to: 'The king entered the room, his crown gleaming in the light'

• NOT 'his crown was gleaming' (which would be a comma splice)

So we need Choice C: highly prized

This makes 'its vehicles highly prized by collectors...' a descriptive phrase providing supplementary information about the period, properly separated by a comma without creating a grammatical error.

GRAMMAR CONCEPT APPLIED

Using Noun + Modifier Constructions for Supplementary Information

When you have a complete sentence and want to add supplementary descriptive information after a comma, you can use a noun followed by a modifier (called an absolute phrase in grammar terms). This structure provides additional detail without creating a new complete clause:

Pattern: [Complete independent clause], [noun + modifier]

Key principle: The modifier uses a participial form (without helping verbs like 'is,' 'are,' 'was,' 'were,' 'has been,' etc.) to keep it descriptive rather than making it a complete clause.

Example 1:

• Incorrect: The ceremony concluded, the audience was applauding enthusiastically.
  • (comma splice - two complete clauses)
• Correct: The ceremony concluded, the audience applauding enthusiastically.
  • (complete clause + noun + modifier)

Example 2:

• Incorrect: The storm passed over the city, its winds were causing significant damage.
  • (comma splice - two complete clauses)
• Correct: The storm passed over the city, its winds causing significant damage.
  • (complete clause + noun + modifier)

In our question:

• Correct: 'this period in automotive design is remembered for its grandeur and artistry, its vehicles highly prized by collectors...'
  • Complete clause + noun ('its vehicles') + modifier ('highly prized by collectors')
  • The participial form 'highly prized' (without 'are'/'were'/'had been') creates a descriptive phrase, not a new complete clause
  • Properly provides supplementary information without a comma splice error