In Romeo and Juliet act 2 scene 4, Mercutio and Benvolio were speaking about Romeo whilst looking for him. It was at this time that they conversed about Tybalt, Romeo's heartbroken-ness and many others. Romeo's mood changed from depressed due to the fact he was depressed about Rosaline, and then became happy because of Mercutio's game of wits and jokes and jests.
So the answer is C. He was depressed but now he is happy.
