Which of the following is equivalent to P ⟺ QP \iff QP⟺Q using only the Sheffer stroke (P∣QP | QP∣Q)?
(P∣P)∣(Q∣Q)(P | P) | (Q | Q)(P∣P)∣(Q∣Q)
(P∣Q)∣(P∣Q)(P | Q) | (P | Q)(P∣Q)∣(P∣Q)
(P∣(Q∣Q))∣(Q∣(P∣P))(P | (Q | Q)) | (Q | (P | P))(P∣(Q∣Q))∣(Q∣(P∣P))
P∣(Q∣P)P | (Q | P)P∣(Q∣P)