Which expression represents the Law of Idempotence for disjunction?
P∨P≡PP \lor P \equiv PP∨P≡P
P∨Q≡Q∨PP \lor Q \equiv Q \lor PP∨Q≡Q∨P
P∨(Q∨R)≡(P∨Q)∨RP \lor (Q \lor R) \equiv (P \lor Q) \lor RP∨(Q∨R)≡(P∨Q)∨R
P∨(P∧Q)≡PP \lor (P \land Q) \equiv PP∨(P∧Q)≡P