Statement `H_(3)PO_(3)` is a dibasic acid and its salt `Na_(2)PO_(3)` does not exist.
Explanation Being dibasic nature, only two `H` are replaceable.
A. (a)If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. (b)If both assertion and reason are true and the reason is not the correct explanation of the assertion.
C. (c )If assertion is true but reason is false.
D. (d)If assertion is false but reason is true.