mi madre ______ (trabajar) en un hospital.\no trabaja\no trabajo\no trabajamos\no trabajan

Brief Explanations:

In Spanish, the subject "Mi madre" (my mother) is third - person singular. The correct present - tense form of the verb "trabajar" (to work) for third - person singular is "trabaja". "Trabajo" is first - person singular, "trabajamos" is first - person plural, and "trabajan" is third - person plural.

Answer:

A. trabaja