Fill in the blank with the most appropriate word.
A verb is used to express an occurrence, action, or state. It is the grammatical centre of the predicate in a sentence.
An auxiliary verb is a verb which gives is used in the formation of tenses, moods, tones, etc.
Option D is correct as the past simple tense is used for an action or a series of actions in the past and the past continuous is used for expressing the idea that at a time in the past we were in the middle of something.
The other options are wrong as only past tense can be used.
The correct answer is D) didn't want