I am an instructor.
A class C is not a disqualifier.
Unless it is for domestic violence which can be under class C misdemeanor and is an automatic disqualifier.
I don't see a Class C Assault offense in the Texas Penal Code that accepts a Domestic Violence enhancement. Which Class C offense does?
It doesn't matter if the class C was against a domestic partner - it matters if the charge was filed (and convicted) with a DV enhancement/modifier. Most Class C offenses never "report" on a criminal history, anyway, as they're considered "local" charges. YMMV, IANAL.