Assertion(A) : If convex lens is kept in water, its convergent power decreases.
Reason(R) : Focal length of lens depends on its refractive index w.r.t. surrounding medium.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is false and R is also false