What comes after C2 in promotion? Is it C3B or C3a whats difference and how much time it takes to move from one promotion to other?

Only thing I can tell you is cut in your performance pay after you get promoted to C3a from C2. So I won't even say u should ever try to get in this band I am there and donating more than 50% every quarter. Hahahhaha

It’s C3A and takes minimum 2 to 3 yrs to move to next level.