Let "U" be the subspace spanned by vectors "u1" and "u2". Find a linearly independent set of vectors that spans "U", so that neither "u1" nor "u2" is a scalar multiple of any of these new vectors. a) "u1" - "u2" b) "u1" + "u2" c) "u1" x "u2" d) "u1" / "u2"