To produce electricity, the loop of wire between the permanent magnets in an electric generator must be moving. Which sentence best explains what makes the motion of the wire necessary? O A. An electric current is induced only if the loop has mechanical energy. B. An electric current exists in the wire only if the magnets have mechanical energy. O C. A magnetic field is induced around the loop only if its electric charges are moving. O D. A magnetic field exists around the magnets only if the loop of wire is moving​