Which of the following is not an antiseptic drug?

The answer is (c) gammexane.

Furacine (a) and Dettol (b) are both antiseptic drugs that are used to kill or prevent the growth of microorganisms on the skin and wounds. Soframicine (d) is also an antiseptic drug that is used to treat and prevent infections caused by bacteria on the skin.

Gammexane (c), on the other hand, is not an antiseptic drug. It is actually an insecticide that is used to kill insects and pests. It is also known as hexachlorocyclohexane (HCH) and has been banned in many countries due to its toxicity and harmful effects on human health and the environment.