The past perfect tense describes an action that was completed before another action in the past. Option C correctly uses the past perfect (had finished) to show the action completed before the simple past (arrived). Option A is incorrect in using present perfect with past. Option B has the past perfect in the wrong clause. Option D does not make any sense gramatically. **Core Concept:** Usage of past perfect tense. **Solution Strategy:** Understanding the sequential relationship of two past actions. **Option Analysis:** * A: Incorrect tense usage, mixing present perfect and simple past. * B: Incorrect sequence of tenses, implies 'I had arrived' was completed after her finishing. * C: Correct use of past perfect to indicate an earlier action in the past. * D: Incorrect sentence structure. **Key Evidence:** The sentence structure in option C shows correct past perfect usage. **Common Mistake:** Confusing simple past and past perfect, and misidentifying which action happened earlier.