Assertion: For a system of particles under central force field, the total angular momentum is conserved.
Reason: The torque acting on such a system is zero.
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.