What happens to the angular velocity of a rigid body if the net external torque is zero?
If the net external torque is zero (dLdt = τ = 0), angular momentum is conserved, and for a fixed moment of inertia, angular velocity remains constant. As per NCERT, applying relevant law/formula with correct units and sign convention leads to It remains constant. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.