The output of a logic gate is 1 when all its inputs are at logic 0. the gate is either
(A) a NAND or an EX-OR (B) an OR or an EX-NOR
(C) an AND or an EX-OR (D) a NOR or an EX-NOR
(A) a NAND or an EX-OR (B) an OR or an EX-NOR
(C) an AND or an EX-OR (D) a NOR or an EX-NOR