The Angular Momentum of a System Is Conserved Only If

Multiple Choice

The angular momentum of a system is conserved only if

A) the angular velocity is a function of time.
B) the sum of the external torques equals the sum of the internal torques.
C) the moment of inertia of the system is constant.
D) the sum of the external torques is zero.
E) the sum of the internal torques is zero.