In most small electric motors, the magnets that are around the central rotor (the field magnets) are the magnet in the center is a(n)
a) horseshoe magnets, bar magnet
b) bar magnets, horseshoe magnet
c) electromagnets, permanent magnet
d) permanent magnets, electromagnet

the answer is  D

Explanation:

In most small motors, the field magnet is usually a permanent magnet (the field magnet could be an electromagnet as well, but in most small motors it isn't in order to save power). The rotor (or armature) is an electromagnet. The pole of the central magnet can be changed to continue its motion when pushed and pulled by the outer permanent magnet.

the rearrangement of particles in a physical change. hope this