The Sequence of Thermonuclear Fusion Processes Inside Massive Stars Can

The sequence of thermonuclear fusion processes inside massive stars can transform elements such as carbon,oxygen,and so forth,into heavier elements AND generate excess energy,until iron has been produced.Why is it not possible for fusion reactions to release energy from iron nuclei?

A) It has been found that iron nuclei never undergo fusion reactions.
B) The magnetic properties of iron produce extra repulsion that,along with the electrostatic repulsion,prevents fusion of iron nuclei with protons.
C) Iron is the heaviest possible element in nature,and fusion of heavier elements is not possible.
D) The electrostatic repulsion between the iron nucleus and the proton is so great that fusion requires extra energy,rather than releasing it.