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 the antimatter that would have been produced at this time.
C) We do not yet have a theory that links the weak and electromagnetic forces.
D) We do not yet have a theory that explains how the universe underwent a rapid period of inflationary expansion.
E) The Planck era was the time before the Big Bang, and we cannot describe what happened before the beginning of the universe.