Nuclear Fission: Which of the Following Descriptions Best Describes the Process

Nuclear fission: Which of the following descriptions best describes the process by which energy is released in a conventional nuclear reactor?

A) The radiation given off by a naturally radioactive substance, uranium, is collected and used to make steam.
B) Uranium is reacted with oxygen in a combustion process that releases large amounts of radioactivity and heat.
C) Deuterium and tritium are joined together to form helium.
D) Uranium, when bombarded by neutrons, splits into fragments and releases two or three neutrons, and these neutrons in turn strike more uranium nuclei that split, thereby setting off a chain reaction that releases energy.
E) A uranium nucleus is energized to an excited state by neutron irradiation, and it then decays by emitting beta rays and gamma rays that heat water and create steam.