Question

which answer is an appropriate response to this question? ¿a qué hora empieza la fiesta? a las dos. son las dos. en las dos. de las dos.

Explanation:

The question "¿A qué hora empieza la fiesta?" asks "What time does the party start?". "A las dos" means "At two o'clock" and is the appropriate way to answer a question about the start - time of an event. "Son las dos" is used to tell the current time. "En las dos" and "De las dos" are not the correct expressions to answer this time - start question.

Answer:

A. A las dos.