A. A frame of reference which is either at rest or moves with a constant velocity is called an inertial frame of reference
B. An un-accelerated frame of reference is called an inertial frame of reference
C. All the frames of reference in uniform rectilinear motion are equivalent
D. Newtons laws of motion are valid in an accelerated (non-inertial) frame of reference
✅ The correct answer is option D.