In 1991, the World Wide Web became publicly available, fundamentally transforming how humans share and access information across the globe....

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

Sentence Structure

• Sentence 1:
  • In 1991,
    • the World Wide Web
      • became publicly available,
        • fundamentally transforming how humans share and access information across the globe.
• Sentence 2:
  • This revolutionary technology
    • emerged from research
      • that its inventor [?] Tim Berners-Lee [?] believed
        • 'could democratize knowledge in unprecedented ways.'

[Where [?] represents the comma placement we need to decide]

Understanding the Meaning

The first sentence sets the scene:

• In 1991, the World Wide Web became publicly available
  • This was a huge transformation in how people share and access information.

Now the second sentence tells us about where this technology came from:

• 'This revolutionary technology emerged from research...'

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

• They all include the same words: "its inventor Tim Berners-Lee believed"
• What varies is the placement of commas around these words.

To see what works here, let's read the rest of the sentence and understand what it's saying!

The complete thought is:

• 'This revolutionary technology emerged from research that its inventor [?] Tim Berners-Lee [?] believed could democratize knowledge in unprecedented ways.'

Now let's really understand what this is telling us:

• 'its inventor'
  • tells us WHO had beliefs about this research
  • it's referring to the person who invented the World Wide Web
• 'Tim Berners-Lee'
  • gives us the specific NAME of that inventor
  • this adds identifying information - telling us exactly which person we're talking about
• 'believed could democratize knowledge in unprecedented ways'
  • tells us what this person (the inventor) thought about the research
  • he believed it could democratize knowledge

So the complete picture is:

• The technology came from research, and the inventor of that technology (specifically, Tim Berners-Lee) believed this research could democratize knowledge.

What do we notice about the structure here?

• We have a general description: "its inventor"
  • This already tells us the relationship to the technology
• Followed by a specific name: "Tim Berners-Lee"
  • This adds the actual name - telling us WHO that inventor is
  • The sentence would still be complete without the name: "research that its inventor believed could democratize knowledge"
  • The name is additional, clarifying information
• When you provide a specific name after a general description like this, and the name is extra information (not essential to complete the sentence), you need to set it off with commas on BOTH sides.

So we need: its inventor, Tim Berners-Lee, believed

The correct answer is Choice D.

Grammar Concept Applied

Setting Off Non-Essential Names and Identifying Information with Commas

When you mention a general descriptor followed by a specific name that provides additional identifying information, you need to set off that name with commas on both sides (called a non-essential appositive in grammar terms). This is because the name is extra clarifying information - the sentence would still be complete and meaningful without it.

The Pattern:

• General descriptor: the inventor
• With specific name added: the inventor, Tim Berners-Lee,
• Complete sentence: The inventor, Tim Berners-Lee, revolutionized the internet.
  • "The inventor revolutionized the internet" is already complete
  • "Tim Berners-Lee" adds the specific name as extra information
  • Therefore: commas on BOTH sides

More examples:

• My sister, Jennifer, lives in Boston.
  • "My sister" = general descriptor
  • "Jennifer" = specific name (additional information)
  • Commas on both sides
• The novel, Pride and Prejudice, was published in 1813.
  • "The novel" = general descriptor
  • "Pride and Prejudice" = specific title (additional information)
  • Commas on both sides

In our question:

• "its inventor" = general descriptor
• "Tim Berners-Lee" = specific name (additional information)
• "believed" = the verb that continues the sentence
• Therefore: its inventor, Tim Berners-Lee, believed

The key test: Can you remove the name and still have a complete, meaningful sentence? If yes, set it off with commas!