Heavy drinkers are about likely to abuse drugs than non-drinkers.
a. equally as
b. four times as
c. nine times as

Heavy drinkers are about C. nine times as likely to abuse drugs than non-drinkers. 
Those who abuse alcohol will also likely abuse drugs as well. This especially refers to heavy drinkers who rely on alcohol to make them forget about their daily lives. At one point, alcohol won't be enough for them, which is why they will also incorporate illegal drugs into their daily lives.

C. medicine can be made from different sources in the forest