Answer:
C but see below.
Step-by-step explanation:
e. The paper clip will likely fall off because it wasn't attached to the nail long enough to be magnetized.
The same answer would apply to the nail. It likely was not held onto the magnet long enough to pick up a magnetic force that would be strong enough to overcome the gravitational force pulling on the clip.
Of the four answers you have given us, I would agree with C. But as I've argued above, the real reason is likely there.