Final answer:
The correct form of the verb 'llamar' in the sentence 'Había una vez una niña que se Caperucita Roja' is 'llamaba'. The verb 'llamar' is in the imperfect tense, used to describe ongoing or habitual actions in the past.
Step-by-step explanation:
The correct form of the verb llamar in the sentence 'Había una vez una niña que se Caperucita Roja' is llamaba.
The verb llamar is in the imperfect tense, which is used to describe ongoing or habitual actions in the past. In this case, it is describing the girl's name or how she was called in the past.
For example: 'Mi hermano se llamaba Juan cuando éramos pequeños' (My brother's name was Juan when we were little).
Learn more about Spanish verb conjugation