Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: A student wraps a wire around an iron nail. The student then connects the wire to a battery. The nail attracts another nail and they stick together. What force holds the two nails together?
magnetic force
Electrostatic force.