Assertion (A): Harshavardhana convened the Prayag Assembly.
Reason (R): He wanted to popularize only the Mahayana form of Buddhism.
(a) Both A and R are true but R is the correct explanation of A
(b) Both A and R are true but R is not a correct explanation of A
(c) A is true but R is false
(d) A is false but R is true