Assertion: Biomagnification of DDT can enhance the decline in bird population.
Reason: DDT causes thinning of egg shell and their premature breaking by disturbing calcium metabolism.
A. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion and Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. If Assertion is true but Reason is false, then mark (3).
D. If both Assertion and Reason are false, then mark (4).