A ball is hit up in the air. At its highest point the ball has the amount of potential energy. Right before it hits the ground it has the
amount of potential energy
: maximum
* minimum

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.