The correct option is B P1 & P3
a) for P2 & P3
Since, a1a2=b1b2≠c1c2≠d1d2
Therefore, planes are not parallel
b) for P2 & P4
Since, a1a2=b1b2=c1c2=d1d2
Therefore, planes are identical
c) for P1 & P3
Since, a1a2=b1b2=c1c2≠d1d2
Therefore, planes are parallel and identical
d) for P1 & P4
Since, a1a2≠b1b2≠c1c2≠d1d2
Therefore, planes are not parallel
Ans: C