The position vectors of three points are `2a -b + 3c, a - 2b + lambda c` and `mu a-5b` where `a,b,c` are non-coplanar vectors. The points are collinear when (A) `lambda=-2, mu=9/4` (B) `lambda=-9/4, mu=2` (C) `lambda=9/4, mu=-2` (D) none of these