A k-regular bipartite graph is the one in which degree of each vertices is k for all the vertices in the graph. Given that the bipartitions of this graph are U and V respectively. What is the relation between them?

• A. number of vertices in u=number of vertices in v
• B. number of vertices in u not equal to number of vertices in v
• C. number of vertices in u always greater than the number of vertices in v
• D. nothing can be said