employer state, LC state, client state

[immitech]

My employer in State A, My GC is file in their branch office State B, My client in State C[Working more than a year].

Where should I file tax? Which state tax system applies to me?

1> Is there a chance to file taxes from state A?
2> Do I have to file only from State C[b'cause I am working since more than a year]
3> Do I have to file from State B[b'cause my labour/gc filed from C.]

thanks in advance?
immitech