Choose x = (x1, x2, x3, x4) in R4. It has 24 rearrangements like (x2, x1, x3, x4) and (x4, x3, x1, x2). Those 24 vectors, including x itself, span a subspace S. Find specific vectors x so that the dimension of S is: (a) 0, (b) 1, (c) 3, (d) 4.