a. Let G be an undirected graph with n vertices. If G is isomorphic, to its own complement how many edges must G have? (Such a graph is called self-complementary.)

b. Find an example of a self-complementary graph on four vertices and one on five vertices.

c. If G is a self-complementary graph on n vertices, where n > 1, prove that n=4k or n=4k+1, for some k∈Z+ (I think this is k subset of Z+)