Assertion: Stereoisomers which are not mirror image of each other are called diastereomers.
Reason: Disasteromers may or may not be optically acitve.
A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true and the reason is the correct explanations of the assertion
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.