Electric motors convert electrical energy to mechanical energy. When the current-carrying coil is placed between the magnetic poles, a force acts on it that causes it to rotate. The image below shows a simple electric motor.

The motor is used to lift metal boxes. How can the motor be changed to be able to lift a heavier box?
A.
add more loops of wire between the magnets
B.
rotate the coil in a counter-clockwise direction
C.
change the polarity of the magnet
D.
decrease the size of the magnets