The third one because tres means three and there are 3 in a trio
It would be "Diana prefiere que nosotros tragamos la comida para las vacaciones" because you have to conjugate the verb "tragar" for Nosotros, so you would replace the "-AR" ending with "Amos".
El papá de juanito exige que su hijo HAGA sus tareas con excelencia
I wish it help you :)
