Assertion: Dark reaction occurs only at night in the stroma of chloroplast
Reason: `CO_(2)` fixation occurs only during `C_(3)` cycle.
A. If both assertion and reason are true and the reason is a correct explanation of the assertion
B. If both assertion and reason are true but reason is not a correct explanation of the assertion.
C. If the assertion is true but reason is false.
D. both are false.