Fully moving the muscles without locking your joint is an example of moving your joint properly through range of motion.
Option A is not correct because If you are locking your joint then youre not properly moving your joint or muscle.
Option B is not correct because this isnt moving through range of motion and is only extended.
Lastly option C is not correct because again you are not fully or completely moving the muscle infact just doing it partially hence not through the range of motions.