Which expression describes the logical operation 'NAND' (Not-AND)?
¬(P∧Q)\neg(P \land Q)¬(P∧Q)
¬P∧¬Q\neg P \land \neg Q¬P∧¬Q
¬P∨¬Q\neg P \lor \neg Q¬P∨¬Q
¬(P∨Q)\neg(P \lor Q)¬(P∨Q)