Why Can't Current Theories Describe What Happened During the Planck

Multiple Choice

Why can't current theories describe what happened during the Planck era?

A) We do not yet have a theory that links quantum mechanics and general relativity.
B) We do not understand the properties of antimatter.
C) We do not know how much energy existed during that time.
D) It was a time period from which we cannot receive radiation.
E) The Planck era was the time before the Big Bang,and we cannot describe what happened before that instant.