Assertion (A) : Ortho phosphoric acid is tribasic acid
Reason (R) : Orthophosphoric acid forms three series of salts.
A. Both (A) and (R) are true and (R) is the correct explanation of (A)
B. Both (A) and (R) are true and (R) is not the correct explanation of (A)
C. (A) is true and (R) is false
D. (A) is false but (R) is true