If `veca,vecb,vecc and vecd` are unit vectors such that `(vecaxxvecb).(veccxxvecd)=1 and veca.vecc=1/2` then (A) `veca,vecb,vecc` are non coplanar (B) `vecb,vecc, vecd` are non coplanar (C) `vecb, vecd` are non paralel (D) `veca, vecd` are paralel and `vecb, vecc` are parallel

Options

A. `veca,vecb,vecc` are non-coplanar
B. `vecb,vecc,vecd` are non-coplanar
C. `vecb,vecd` are non-parallel
D. `veca,vecd` are parallel and `vecb,vecc` are parallel

Answer

C