Question

cuando _________ niño, yo comía mucho helado.

Explanation:

The subject is "yo" (I), and the verb "ser" (to be) in the imperfect tense for "yo" is "era". The sentence is in the past - imperfect tense, indicating a habitual action in the past. The other options are for plural subjects or incorrect conjugations for "yo".

Answer:

A. era