Who do yu think is the bby daddy ???

My friend had sex with two guys this month shes not sure who=/ guy A: around 5th of may she used protection and she was finishing her period tht exact day also she Noticed her blood was a lil brown after sex but ithink cuz she was finishing her period Guy B Around 16 of may no protection but Like a day after having sex with guy B she felt like throwing up but i thinks thts way to early for symtoms what do yu think n why!!!