Questions about NROTC Marine Option?

I am going to MCRD boot camp early next year. I want a college degree. My recruiters said if I did active duty, the Corps would pay for full tuition in college when I am not deployed or do online courses when deployed. Do they only pay for ROTC or can I can pick something else? and also, if i get deployed and im 1/2 way through the course do I just lose all my progress that I was working on before?