Answer: The correct answer is A. Hace.
Step-by-step explanation:
The correct form for expressing this saying is by using "hace", so the outcome is "¿Qué tiempo hace?". The typical response to this question (which means "What's the weather like?") is "Hace frío" or "Hace calor", so both the answer and question are coherent in the correct use of the verb. It's not typical to hear "hay", although in countries like Peru or Argentina, it's possible that people say "¿Cómo está hoy el clima?" (this one is a more loyal translation of "How's the weather like today?") o "¿Cómo está el tiempo?