A graph which has the same number of edges as its complement must have number of vertices congruent to ______ or _______ modulo 4(for integral values of number of edges).

A graph which has the same number of edges as its complement must have

1.	A graph which has the same number of edges as its complement must have number of vertices congruent to ______ or _______ modulo 4(for integral values of number of edges).
A.	6k, 6k-1
B.	4k, 4k+1
C.	k, k+2
D.	2k+1, k
Answer» D. 2k+1, k