If `veca, vecb and vecc` be any three non coplanar vectors. Then the system of vectors `veca\',vecb\' and vecc\'` which satisfies `veca.veca\'=vecb.vecb\'=vecc.vecc\'=1 ``veca.vecb\'=veca.veca\'=vecb.veca\'=vecb.vecc\'=vecc.veca\'=vecc.vecb\'=0` is called the reciprocal system to the vectors `veca,vecb, and vecc`. The value of `(vecaxxveca\')+(vecbxxvecb\')+(veccxxvecc\')` is (A) `veca+vecb+vecc` (B) `veca\'+vecb\'+vecc\'` (C) 0 (D) none of these