The measure of a coil's ability to produce flux is called

Explanation:

Electromotive force - It is the difference in potential that results in a electric current in the circuit     

Magnetic lines of force- These are imaginary lines which represent the direction of magnetic field.They appear to emerge from the north pole and terminate at the south pole ,inside the magnet the magnetic field lines is directed from the south pole to the north pole .

Magnetomotive force - It is the property of certain substance (here coil) to produce magnetic flux .

Magnetism- It is the property of the magnet through which it attracts or repel other entity. 

Hence the correct option is 3