. Let T: R R be defined by T (x, y, z) = (x, y, 0) and S:R R be defined by S(x, y) = (2x, 3y), be linear transformations on the real vector spaces R and R respectively. Then, which one of the following is correct? (a) T andS are both singular. (b)_T andS are both non-singular. Tis singular and S is non-singular. (d) S is singular and T is non-singular.