Which of the following is not correct? 1 )`AsubeA^c` if and only if `A=phi` 2) `A^csubeA` if and only if A = X , where X is a universal set 3)If A UB = A UC , then B = C 4) A = B is equivalent to AUC = BUC and `AnnC=BnnC`

Options

A. `AsubeA`' if and only if `A=phi`
B. `A'subeA` if and only if A = X, where X is the universal set
C. if `AuuB=AuuC`, then B = C
D. B = C if and only if `AuuB=AuuCandAnnB=AnnC`

Answer

C