Comem(os), Jugam(os), Peliam(os) Comenzam(os). In other words pronouns that end in (os).
Answer: Cuestan.
Explanation: Cuanto means How much in english, so the question is asking how much those books are going to cost. Whenever you see a Cuanto in a question like that, assume it's talking about a number of something, or money. So Cuestan means cost, in the terms of "How much does this item cost?".
D. Mandar ( between quiere and dinero)
What do you mean if there is an answer already ?
