Actually the correct answer is D. tendrá. Because A would be if you were talking about yourself. B would be if you were taking about a group including yourself, and C would be right if you were talking about a group not including yourself.
The third one because tres means three and there are 3 in a trio
Answer:
How about saying this instead:
Mi hermano tiene diecinueve años y creo que es perezoso y aburrido.
Explanation:
