Option B is a completely different approach depending on your individual needs:
Keep dot net on a different server using a different DNS. Redirect any request for dot net except the front page to the same page in dot com. If your "real" site, dot com, is ever down, type-ins may then say "Uhm, maybe I got it wrong, let me try net" and then they get to dot net's front page.
Admittedly this scenario is more likely if the primary is something other than dot com.