For an Object Rotating About a Fixed Axis, Where $\alpha$ Is Its Angular Acceleration

Multiple Choice

for an object rotating about a fixed axis, where is the net torque acting on it, I is its rotational inertia, and $\alpha$ is its angular acceleration.This expression:

A) is the definition of torque
B) is the definition of rotational inertia
C) is the definition of angular acceleration
D) follows directly from Newton's second law
E) depends on a principle of physics that is unrelated to Newton's second law