Question

Match the following antibodies with their correct description:

Antibody	Description
P. IgE	(i) Cross the placenta
Q. IgG	(ii) Dominant antibody produced in immune responses
R. IgM	(iii) It is found in the mother's milk
S. IgA	(iv) Responsible for autoimmune responses including allergies

• A. P(i), Q(iii), R(ii), S(iv)
• B. P(i), Q(ii), R(iii), S(iv)
• C. P(iv), Q(ii), R(iii), S(i)
• D. P(iv), Q(i), R(ii), S(iii)

Answer 1

The Correct Option is D

The correct option is (D): P(iv), Q(i), R(ii), S(iii).

Answer 2

This question tests recall of the defining functional property of each immunoglobulin class: IgG crosses the placenta, IgM is the first and most abundant antibody produced in an immune response, IgA is secreted in mother's milk, and IgE mediates allergic and autoimmune-type hypersensitivity reactions. Using this, each proposed matching can be checked directly:

1. P(i), Q(iii), R(ii), S(iv): This places IgE with "crosses the placenta," which is a property of IgG, not IgE, so this arrangement is incorrect.
2. P(i), Q(ii), R(iii), S(iv): Here IgE is again wrongly paired with "crosses the placenta" and IgA is paired with "responsible for allergies," a role that belongs to IgE, so this arrangement is also incorrect.
3. P(iv), Q(ii), R(iii), S(i): IgE correctly links to allergic responses, but IgG is paired with "dominant antibody produced in immune responses" (which describes IgM) and IgG is expected to cross the placenta rather than appear in milk, so this arrangement mismatches Q, R and S.
4. P(iv), Q(i), R(ii), S(iii): IgE is correctly linked to allergic and autoimmune responses, IgG correctly crosses the placenta, IgM is correctly the dominant antibody of the immune response, and IgA is correctly found in mother's milk. Every pairing matches the known property of that antibody class.

Only the last arrangement pairs every antibody with its correct functional description.

Therefore, the correct answer is P(iv), Q(i), R(ii), S(iii).