Topic: Dangling Modifer,

Best Answer Explained in Below-:

The question "Nobody knows why __ postponed until next week" requires a grammatically correct and contextually appropriate completion. The correct answer is "the meeting was" (Option D).

In this sentence, "nobody knows" serves as the main clause, implying a lack of knowledge about a specific event—the postponement. The structure of the blank requires an explanation that follows the rules of indirect speech or embedded clauses.

Here's why the other options fall short:

- **A) is the meeting:** This option incorrectly uses the present tense "is," which does not align with the past action of postponement.
- **B) was the meeting:** This formulation incorrectly positions the subject "the meeting" before the verb, creating an awkward sentence structure that doesn't convey the intended meaning.
- **C) did the meeting:** This option uses "did," which implies an action but does not make sense in the context of postponement, making it grammatically incorrect in this context.

In contrast, "the meeting was postponed" is a clear past passive construction where "the meeting" is the subject and "was postponed" correctly indicates that the action occurred in the past. Overall, option D maintains the sentence's coherence and clarity, making it the best choice.