The verb that best completes the question: ¿Cuántos perros hay en la casa? es: "Hay"/are
Explanation:
First of all the question asks about some dogs in a house. So:
Va is a verb that translates to go in English and our case is conjucted in singular not plural. So it's wrong because we are talking about dogs not a dog.
Son is a verb that translates to are in a form of being and plural this could be a good option. But it's incorrect because the proper question to ask about the number of dogs in a certain house should be "hay" of having because they are objects not persons, and son is a verb to represent a state of being.
Hay is the correct answer because we translate "Hay" like are in a way of having. We don't talk of dogs as persons but as objects. Also it is conjuctedin plural.
Fue is a verb that translates to went and we are reading the sentence in present so past verb is wrong.
