The torque `vec tau` on a body about a given point is found to be equal to `vec A xx vec L` where `vec A` is a constant vector and `vec L` is the angular momentum of the body about the point. From this its follows that -

Options

A. `(dvecL)/(dt)` is perpendicular to `vecL` at all instant of time
B. The component of `vecL` in the direction of `vecA` does not change with time
C. The magnitude of `vecL` does not change with time
D. `vecL` does not change with time