Answer:
C. The magnet will become stronger
Step-by-step explanation:
It is not A because an electromagnet runs off of the electrical fields and magnetic fields of the nail and wires therefore it will not make the magnet weaker.
It is not B because the poles of the magnet do not switch just from an increase in strength of the magnetic and electrical field.
It s not D because as soon as the current stops the magnet loses its strength and eventually stops being magnetic.