Final answer:
The appropriate verb to fill in the blank is 'tienes'.
Step-by-step explanation:
The appropriate verb to fill in the blank in the sentence '¿Cuántos años tienes?'' is B. tienes. The sentence is asking 'How old are you?'. In Spanish, when we want to ask someone's age, we use the verb 'tener' which means 'to have'. So, the correct answer is '¿Cuántos años tienes?'.
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