The correct answer is: A. Have visited.
The verb “have visited” is used to talk about past experiences. It is used to ask about or talk about whether someone has done something before. In this case, the question is asking whether the person has ever visited Manali.
The verb “had visited” is used to talk about past experiences that happened before a certain point in time. It is used to ask about or talk about whether someone had done something before a certain point in time. In this case, the question is not asking about whether the person had visited Manali before a certain point in time.
The verb “did visit” is used to talk about specific events that happened in the past. It is used to ask about or talk about what someone did on a specific occasion. In this case, the question is not asking about what the person did on a specific occasion.
The verb “will be visiting” is used to talk about future events. It is used to ask about or talk about what someone will do in the future. In this case, the question is not asking about what the person will do in the future.