Final answer:
The correct form of the verb 'gustar' to use in this sentence is 'gusta' because the subject is singular.
Step-by-step explanation:
The correct form of the verb 'gustar' to use in this sentence is gusta.
'Gustar' is a Spanish verb that is used to express likes and dislikes. It is conjugated based on the thing or activity being liked, not the person doing the liking. In this sentence, the subject is 'el chocolate', which is singular, so the correct form of 'gustar' to use is 'gusta'.
Example: Me gusta el chocolate. (I like chocolate.)
Learn more about Using the correct form of 'gustar' in Spanish sentences