Assertion: `NaHSO_(3)` is used in separation and purification of aldehydes.
Reason : `NaHSO_(3)` is reducing agent.
A. If Both assertion and reason are true reason is the correct explation of the assertion.
B. If Both assertion and reason are true but reason is not the correct explation of the assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.