Using her medium dp has upper body invincibility that you can use as an anti air. She’s a bit like Guile in that she has a lot of situational anti airs (but not as much). I would say st mp is probably the safest bet, you can also try st mk.
Just for the record, c.fierce beats every sagat jump in clean. I think j.lk may sometimes trade with it but only at a specific crossup angle