His reckless remark did not go unnoticed.

Analyze the question: The underlined word is "reckless" (in "His reckless remark did not go unnoticed"). We need the option closest in meaning.

Explain the concept: "Reckless" means acting without thinking about the consequences; careless, rash, thoughtless. A reckless remark is one made without caution or care about what it might cause.

Check each option:

• A. salient: means prominent or most noticeable. This is about being striking, not about carelessness. ✘
• B. considerable: means large in amount or degree, or worthy of consideration. It doesn't fit. ✘
• C. taciturn: means quiet or reserved in speech. A person who is taciturn says little, so it is nearly the opposite of making a remark. ✘
• D. unguarded: means not careful about what one says or does, so it is said without caution or thought. This matches "reckless" in this context. ✔

Answer: D. unguarded.

Tip: In "nearest in meaning" questions, replace the underlined word with each option and read the sentence aloud. "His unguarded remark did not go unnoticed" makes sense and keeps the original meaning. Also watch for words that describe speech, like "remark", "comment", or "statement". They often pair with words like "careless", "rash", or "unguarded".