Answer:
The right answer is, Chocó.
* Llovía cuando el autobús chocó con el coche.
Step-by-step explanation:
Because the past tenses and imperfect tenses are used in actions that were performed in the past tense, therefore we must identify the person and the time in the sentence to be able to conjugate the verb in a logical way and that is consistent with what is being expressed.