Assertion: Insulin is a globular protein.
Reason: It has two polypeptide chains with 21 and 30 amino acids.

a) Both assertion and reason are true, and reason is the correct explanation of the assertion.
b) Both assertion and reason are true, but reason is not the correct explanation of the assertion.
c) Assertion is true, but the reason is false.
d) Assertion is false, but the reason is true.