Determine which of the following subsets of Rn are in fact subspaces of Rn (n > 2). If it doesn't satisfy the question, please write down the reason.
a) {x | x = 2, 0} - False
b) {x | x = 0} - True
c) {x | x, z != 0} - False
d) {x | Is - x = 0} - False
e) {x | Ix; -, x; = 1} - False
f) {x | Ax = b, where A != 0 and b != 0} - True