Option (2) is the answer because heroin, commonly called smack is chemically diacetyl morphine. Morphine is used as sedatives.
Option (1) is not the answer because cocaine is obtained from coca plant and commonly called coke or crack.
Option (3) is not the answer because amphetamine is a stimulant.
Option (4) is not the answer because, barbiturates belong to the categories of sedatives.