To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?

The total energy used to move the truck is

(the amount of energy from burning gasoline)

plus

(the amount of energy taken out of the battery) .

(We don't know how much either of those is.)

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.