Answer:
A: Hablan
Explanation:
Los estudiantes is plural so you would use the ellos conjugation of the verb hablar, which is hablan.
4th one. Carmen caminaba a la playa.
The first one is using the nosotros form. The second one is using preterite but using the yo form. The third is using the you form.
The 4th one is saying it was a continuos activity and it was talking about a specific person.
