Which vector spaces are isomorphic to r6? (a) m3,2 isomorphic to r6 not isomorphic to r6 (b) p5 isomorphic to r6 not isomorphic to r6 (c) c[0, 6] isomorphic to r6 not isomorphic to r6 (d) m1,6 isomorphic to r6 not isomorphic to r6 (e) p6 isomorphic to r6 not isomorphic to r6 (f) {(x1, x2, x3, 0, x5, x6, x7): xi is a real number} isomorphic to r6 not isomorphic to r6?