A particle stays at rest as seen in a frame. We can conclude that

If the particle is in rest in an inertial frame, then the resulting force is zero and thus the frame is inertial by definition.


If the particle is not in inertial frame, then the resulting forces are not zero. Since the particle can be moving with the same acceleration as that of the non-inertial frame and thus the resulting force is not zero.


Hence option C and D are correct.

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