Why Can't We See Past the Cosmological Horizon

Multiple Choice

Why can't we see past the cosmological horizon?

A) The universe extends only to this horizon.
B) Beyond the cosmological horizon,we are looking back to a time before the universe had formed.
C) We do not have telescopes big enough.
D) We do not have sensitive enough detectors.
E) The cosmological horizon is infinitely far away,and we can't see to infinity.