It would be C and D.
A is not an answer since many people drink many different types of alcohol and it doesn't mean that they are alcoholic. They are just trying new things.
B is not an answer since quitting is not a sign of alcoholism because the problem has already been addressed.
C and D are answers since alcoholism takes over someone's life so much to the point where they drink a lot. Usually it is alone since some are very embarrassed and don't want to show everyone else how much they consume due to self-consciousness so they don't go to other activities.
