The widely accepted big bang theory holds that the
universe began in an explosive instant ten to twenty
billion years ago and has been expanding ever since.
(A) that the universe began in an explosive instant
ten to twenty billion years ago and has been
expanding
(B) that the universe had begun in an explosive
instant ten to twenty billion years ago and had
been expanding
(C) that the beginning of the universe was an
explosive instant ten to twenty billion years ago
that has expanded
(D) the beginning of the universe to have been an
explosive instant ten to twenty billion years ago
that is expanding
(E) the universe to have begun in an explosive
instant ten to twenty billion years ago and has
been expanding

A

I agree that this is the best of the choices given, but here is my question:

The theory holds two things -- that it began....and that it has been expanding.... I'm not clear how omitting the second that is OK.