Malik built a simple electromagnet with copper wire, an iron bolt, and a 1.5-volt battery. The electromagnet was able to lift a paper clip from 3 centimeters away. Select three ways Malik can improve the strength of his electromagnet.

A.
He can use a thicker piece of copper wire.

B.
He can reverse the orientation of the battery.

C.
He can replace the iron rod with a wooden rod.

D.
He can add a switch between the battery and the iron bolt.

E.
He can replace the 1.5-volt battery with a battery of higher voltage.

F.
He can use a longer piece of wire that wraps more times around the bolt.

I'd say F and E but I'm not sure about the other one.