Question

el domingo pasado ( visitaba / visité ) a mi madre.

Explanation:

In Spanish, the preterite tense (pretérito) is used for completed actions in the past, while the imperfect (imperfecto) is for ongoing or habitual past actions. "El domingo pasado" (last Sunday) refers to a single, completed action, so the preterite form "visité" is correct. "Visitaba" is imperfect and would be used for actions like "I used to visit" or "I was visiting" (ongoing/habitual in the past).

Answer:

visité