Answer:
1. Tú comprendes las matemáticas.
2. Nosotros limpiamos la casa el viernes porque hay fiesta el sábado.
3. Ellos escuchan música cuando asisten el concierto en el parque.
4. Yo pregunto si hay tarea.
Answer: Hablan
Explanation: B is hablamos, which will be used if it says we. C is habla, which is describing another person (singular). D is hablas, which is talking about you (tu). So the answer will be a, hablan, because it is talking about they, and in plural version. If its singular, it will be habla. Family consists of multiple members, so it wouldn’t be singular.