The k -cube is the graph whose vertices are the ordered k -tuples of O's and 1's, two vertices being joined if and only if they differ in exactly one coordinate.

Consider the following statements about K-cube graph

S1: It has vertices

S2: It has edges

S3: It is a bipartite graph

Which one of the following statements is true?

A. Only S1

B. Only S1, S2

C. Only S1, S3

D. All of S1, S2, and S3