6.2.3 Determine whether the following statements are true or false (in (b), the symbol ( means proper subset). Justify your answers. (a) If f7g 2 P(A), then 7 2 A and f7g 2/ A. (b) Suppose that A, B and C are sets such that A ( P(B) ( C and jAj = 2. Then jCj can be 5, but jCj cannot be 4. (c) If a set B has one more element than a set A, then P(B) has at least two more elements than P(A). (d) Suppose that the sets A, B, C and D a