Thank you.

Consider three relations with the following schemas: R(AB), R2(AB), S(CD). Which of the identities in the Relational Algebra below hold? a. (R - R2) - R2 = R b. ((R-R2) - R2) - R2) = R C. TA (R BECS) = TIA(R) d. MABOR BECS) - R2 = TAB((R - R2) B-C S) e. None of them holds