Identify the following statements as true or false.

(a) A subset H of Rn is a subspace if the zero vector is in H.
(b) Given vectors v1,..., vp, in Rn, the set of all linear combinations of these vectors is a subspace of Rn.
(c) The null space of an m x n matrix is a subspace of Rn.
(d) The column space of a matrix A is the set of solutions of Ax=b.
(e) If B is an echelon form of a matrix A, then the pivot columns of B form a basis for Col A.