Assertion: A solid sphere cannot roll without slipping on smooth horizontal surface.
Reason: If the sphere is left free on smooth inclined surface, it can roll without slipping.
Options:
(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.