Question

fill in the blank: ¿a ______ vas? (\where are you going?\)
qué hora?
cuándo
dónde

Explanation:

To answer this, we analyze each option: "qué hora?" means "what time?" and is used to ask about time, not location. "cuándo" (note: correct spelling is "cuándo" but it means "when" and is for time - related questions). "dónde" means "where" and is used to ask about location, which fits the context of "Where are you going?".

Answer:

dónde