Ace the TSA CBT Exam 2025 – Get Ready to Fly Through with Confidence!

The correct choice focuses on the defining characteristic of a restrictive clause. A restrictive clause is essential to the meaning of a sentence because it provides necessary information about the noun it modifies. This means that if you were to remove the restrictive clause, the sentence would lose important context and its meaning would change significantly.

For instance, in the sentence "The book that I borrowed was fascinating," the phrase "that I borrowed" is a restrictive clause. If we removed it, the sentence becomes "The book was fascinating," which could imply any book, rather than specifying which one was fascinating.

The other options do not accurately describe restrictive clauses. While restrictive clauses are not typically set off by commas, they do not always start with specific words like "however" or are irrelevant to whether they can be phrased as questions. Thus, the specific criterion that dictates the necessity of the clause for meaning makes the identifying characteristic clear.