The correct option is C I wouldn' t have to
Let’s examine the sentence: “I have to go to a dentist tomorrow. I wish ____.” There are two sentences and the second sentence talks about an imaginary a situation, unlikely to happen. This sentence makes use of the second conditional that is used to express imaginary and impossible situations. So, second conditional used forms of verbs in past tense. In case of second conditional, when ‘I/we wish’ is used to talk about a regret about a present or future event, then the expressions ‘I/We wish’ is followed by past simple. However, as this sentence talks about a future event, a past simple verb usually used in the sense of future tense is required here. So, ‘would’ is required here as verb. Hence, Option C is the correct answer here. Other options cannot be used as they would render the sentence grammatically incorrect.