The first sentence is in simple past tense. It states an action 'couldn't visit' in the past moment. 'Could' is a past tense modal verb. The second sentence 'not enough time' is the reason behind the first 'couldn't visit the museum'.
Hence the second sentence will also be in past tense.
Option C: 'Didn't have' is in simple past tense and states an action that happened in the past. It's the most appropriate option, expressing the past tense. Hence option C is correct.
Option A: 'Don't have' expresses the simple present tense, as opposed to the past action here 'couldn't'.
Option B: 'Hadn't have is not a correct phrase. 'Had' in 'had not' is a past tense verb and 'have' refers to the present.
('Haven't had' is correct since 'have' expresses the present perfect, along with the past participle 'had')
Option D: We use the past participle 'had' after 'haven't' to express the present perfect tense. But the present tense verb 'have' is not used as a main verb in a perfect tense.
The first 'have' is an auxiliary and the second 'have' is the main verb.
Hence options A, B and D are wrong.