With reference to monoclonal antibodies, often mentioned in news, consider the following statements:I.They are man-made proteins.II.They stimulate immunological function due to their ability to bind to specific antigens.III.They are used in treating viral infections like that of Nipah virus.Which of the statements given above are correct?

1. A

   I and II only

   I and II only. That drops the Nipah/viral-use line, which is keyed.

2. B

   II and III only

   II and III only. That drops the man-made-protein line.

3. C

   I and III only

   I and III only. Monoclonal antibodies are laboratory proteins, and they are used against some viral infections (including Nipah protocols). II is not in the official pair.

4. D

   I, II and III

   I, II and III. II is the extra limb.

Summary. Official Set A key is (c) I and III only. Monoclonal antibodies are engineered proteins that bind a chosen antigen. They are used in several viral treatments and were discussed for Nipah. Statement II’s wording — that they stimulate immunity because they bind antigen — is the distractor: many mAbs neutralise or flag a target; they are not a general immune stimulant. So I and III are scored; II is not.