A Proton Is Maintained at Rest in the Middle of a Box

Multiple Choice

A proton is maintained at rest in the middle of a box that has no matter inside it other than the single proton. Assuming that the box is isolated from all external influences, which of the following would we expect to find at some other point X inside the box?

A) a magnetic field
B) an electric field
C) Both of the above.
D) an electric force
E) All of the above.