If you have a twenty eight day cycle, then you most likely ovulated around the 26th. So I would say B. But just remember that is not exact and sperm can live for 72 hours, so if you ovulated a little earlier then it could be A. The best bet is a paternity test.
Exactly its depends on your cycle. I know mine is 38 days so I ovulate on day 14 normally. But they can come a day or 2 earlier. Ovulation can be between 11 and 16. Best to get blood test then try and work out.uBut if not one way or other way paternity test.
Oops meant to say 28 days lol
There is no way to know whom the father is until you do that test... You slept with them both with a 7 day period so just go ahead and tell them both and let them prepare to have to take a test... What ever you do don't make it Hardee than it has to be... Good luck!!!