He __________ in Karachi since 2020.

The correct answer is C: has lived. This sentence requires the present perfect tense because it describes an action that started in the past (in 2020) and continues up to the present moment. The keyword "since" is a strong indicator for the present perfect tense, as it specifies the starting point of an action or state that is still ongoing. The structure of the present perfect is "has/have + past participle." In this case, "He" is a third-person singular subject, so "has" is used, followed by the past participle of "live," which is "lived." Options A ("lives") is simple present, implying a habitual action without a specific start date. Option B ("lived") is simple past, suggesting the action ended in the past. Option D ("living") is a present participle and cannot stand alone as the main verb in this sentence without an auxiliary verb (e.g., "is living" for present continuous, which would imply a temporary action). Therefore, "has lived" accurately conveys the continuous nature of his residence in Karachi from 2020 until now.