The correct answer is "had" because it is in the past subjunctive form of the verb "have", which is used in conjunction with "wish" to express a hypothetical or unreal action or condition in the past. In this sentence, the speaker is expressing regret or disappointment about not having more time to prepare for the presentation, but this is a hypothetical or unreal situation because the time has already passed.

Option "have" is incorrect because it is in the present form of the verb, which is not appropriate to express a hypothetical or unreal action in the past.

Option "would have" is incorrect because it is in the past conditional form of the verb, which is used to express a hypothetical or unreal action in the future.

Option "will have" is incorrect because it is in the future form of the verb, which is not appropriate to express a hypothetical or unreal action in the past.