Detailed Examination of the Cosmic Microwave Background Suggests That the Material

Multiple Choice

Detailed examination of the cosmic microwave background suggests that the material from which it scattered had been re-ionized. What do we believe to be the source of this reionization?

A) The cosmic microwave background itself caused the reionization of hydrogen and helium.
B) Large, hot Population III stars emitted enough high-energy radiation during their lifetimes to cause reionization.
C) The intense background of neutrinos and antineutrinos released much earlier than the cosmic microwave background radiation had enough energy to cause reionization.
D) The explosions of giant Population III stars would cause a shower of high-speed particles that could result in reionization.