Find the WR conflict transaction from the following :
1
R2(X), R2(Y), R1(X), R1(Y), W1(X), W2(X) …………….
2
R2(X), R2(Y), R1(X), R1(Y), W1(X)...........
3
R2(X), R2(Y), W2(X), R1(X), W1(Z), W2(Y)............
4
R2(X), R2(Y), W2(X), R1(Y), W1(Z), W2(Y)...............