Who says the following and why?

". . . [N]ow art thou what thou art, by art as well as by nature: for this drivelling love is like a great natural, that runs lolling up and down to hide his bauble in a hole."

A. Mercutio is celebrating the return of the "real" Romeo and comparing love to a slobbering idiot.
B. Romeo is telling his friends that he is over Rosaline (finally!).
C. Nurse is telling Romeo that although she thought Paris was a better match, she feels that Romeo is the one for Juliet.
D. Friar Laurence is commenting the strange behavior of young men in love.