Select the word segment that can substitute the bracketed word segment correctly and complete the sentence.
The detective (had been solved the murder mystery) within a week.

Correct option is B

The correct substitution of the highlighted words is (b) solved the murder mystery.
Explanation: The verb form “had been solved” is passive voice, which is incorrect here. The subject "detective" is the doer, so it must be active voice with simple past tense – “solved”.
Correct sentence: The detective solved the murder mystery within a week.
Grammatical Rule Used:
Subject (doer) + V2 (past tense) + object for completed past actions.
Information Booster:
“Had been + V3” → used in passive voice, not suitable with active subject like detective here.