Select the correct word for the blank in this sentence. I talked to the detective ___ solved the case.

Rationale: The correct answer is B, "who." In this sentence, the relative pronoun "who" is used to refer to the detective as the subject who solved the case. The pronoun "who" is used to introduce a defining relative clause that provides essential information about the detective. Choices A, C, and D are incorrect because "whose" is possessive, "which" is used for things, and "whom" is the object form of "who" and would not be correct here as the detective is the subject of the sentence.