Give an example of each of the following, or explain why no such example can exist.
(a) A 3 Ã 3 matrix A such that the system Ax = 0 has no solutions.
(b) A 3 Ã 3 matrix A such that the system Ax = 0 has infinitely many solutions.
(c) A 3 Ã 3 matrix A such that the system Ax = 0 has exactly one solution.