Right choice is (a) antiviral
Easy explanation: Lysozyme is involved in bacterial cell wall hydrolysis, hence used as an antibacterial. Whereas, Ribonuclease is involved in RNA hydrolysis and has antiviral activity. Hence it can be used in treating viral infections. Penicillin allergy is treated by using β – Lactamase. Blood clots can be treated by using streptokinase and urokinase. Skin ulcers are treated by using collagenases.