In Act II, Scene I, when Mercutio cannot find Romeo
after the Capulet party, what does he think Romeo is
doing

Mercutio thinks Romeo has gone sulking into the night over Rosaline.

this answer was editing it cause i couldn't delete!

most likely the answer would be a.) cupidity

definitions:

cupidity - greed for money or possessions

hydrophobia - extreme or irrational fear of water, especially as a symptom of rabies in humans

pathology - the science of the causes and effects of diseases, especially the branch of medicine that deals with the laboratory examination of samples of body tissue for diagnostic or forensic

patho -   relating to disease