A bob of mass m attached to an inextensible string of length / is suspended from a vertical support . The bob rotates in a horizontal circle with an angular speed $\;w\;$ rad/s about the verticle . About the point of suspension :

Question

(a) angular momentum is conserved.\[\](b) angular momentum changes in magnitude but not in direction.\[\](c) angular momentum changes in direction but not in magnitude.\[\](d) angular momentum changes both in direction and magnitude.