Let's match each drug from List-I to its correct class in List-II.
(a) Furacin (active ingredient is nitrofurazone) is a topical antibacterial agent applied to the skin to prevent or treat infections. This falls under the class of Antiseptics. So, (a) matches with (iii).
(b) Arsphenamine (also known as Salvarsan) was developed by Paul Ehrlich and was the first effective chemotherapeutic agent for syphilis. It is classified as an Antibiotic. So, (b) matches with (i).
(c) Dimetone (active ingredient is brompheniramine) is a medication used to treat allergy symptoms like runny nose and watery eyes. It is a Synthetic antihistamine. So, (c) matches with (iv).
(d) Valium (active ingredient is diazepam) is a benzodiazepine drug that produces a calming effect. It is used to treat anxiety, seizures, and muscle spasms. It is a well-known Tranquilizer. So, (d) matches with (ii).
The correct set of matches is (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii).