If `veca+vecb ,vecc ` are any three non- coplanar vectors then the equation `[vecbxxvecc veccxxveca vecaxxvecb]x^(2) + [veca+vecbvecb+veccvecc+veca] x+1 +[vecb-veccvecc -vecc-vecaveca -vecb] =0` has roots
A. real and distinct
B. real
C. equal
D. imaginary