The correct option is A interesting
Adverbs modify verbs, adjectives and sometimes other adverbs in a sentence.
In this sentence, The adverb, 'quite' is modifying the adjective 'interesting'. It states the extent to which the movie was interesting. Hence, Option C is correct.
Option A is incorrect as 'quite' is the adverb itself.
Option B is incorrect as 'movie' is a noun. Adverbs don't modify nouns.
Option D is incorrect as 'is' is the auxiliary verb which is not being modified by the adverb in this sentence.