A regular graph:

A. must be a cycle graph or complete graph

B. is simple

C. is where every vertex has the same degree as the other vertices

C. Is where every vertex has the same degree as the other vertices

Step-by-step explanation:

A regular graph of degree r is one that has all its local degrees the same number r. This is to mean each of its vertex has the same number of neighbors. Here, every vertex has same degree/valency.