c .es would be my answer , but b also applies if you are talking to him directly and saying it as a compliment , c would be if you are just talking about him to someone else
mas means more
menos means less
you can use them to compare two things or people eg. ciara es mas alta que alex. ciara is more taller than alex. always remember that mas+ the adjective+ que.
same for menos eg. ciara es menos inteligente que tu. ciara is less intelligent than you, menos+adjective+que
Ellos vendrían is a transition
