The question examines the usage of the past perfect tense. The past perfect tense (had + past participle) is used to indicate an action that happened before another action in the past. Option C correctly demonstrates this. Option A uses present perfect which implies a connection to the present. Option B uses simple past tense, and Option D uses future tense which does not reflect past perfect. Therefore, the only correct answer is Option C. * **Core Concept:** Usage of past perfect tense * **Solving Strategy:** Determine the correct tense to show an action prior to another in the past. * **Option Analysis:** * **A:** Incorrect. Uses present perfect tense, not past perfect. * **B:** Incorrect. Uses simple past tense, does not indicate prior action * **C:** Correct. Uses past perfect tense correctly, showing a prior action in the past. * **D:** Incorrect. Uses future tense. * **Easy Mistakes:** Confusing past perfect with simple past or present perfect tense.