If ` vec a , vec b , vec c , vec d` are non-zero, non collinear vectors and if `( vec aX vec b)X( vec cX vec d)dot( vec aXvec d)=0` , then which of the following is always true. (a) ` vec a , vec b , vec c , vec d` are necessarily coplanar (b) either ` vec a` or ` vec d` must lie in the plane of ` vec b` and ` vec c` (c) either ` vec b` or ` vec c` must lie in plane of ` vec a` and ` vec d` (d) either ` vec a` or ` vec b` must lie in plane of ` vec c` and ` vec d`