Lisa made the electromagnet shown. A nail with wire coiled around it has its head labeled S to the right and its point labeled N to the left. The end of the wire leading to the S is attached to the positive terminal of a battery. The end of the wire leading to the N is attached to the negative terminal of the battery. What can Lisa do to increase the strength of the electromagnet? She can use a nail with weaker magnetic properties. She can change the direction of the nail. She can increase the number of wire loops. She can reduce the current in the wire.