Answer
We can draw a graph with four vertices with edges AB, AC, BD, and CD. Then the degree of each vertex is 2, so each vertex is an even vertex.
Since each vertex is even, this is a graph with four even vertices.
Work Step by Step
The degree of a vertex is the number of edges connected to the vertex. If the degree of a vertex is an even number, then the vertex is an even vertex.
We can draw a graph with four vertices with edges AB, AC, BD, and CD. Then the degree of each vertex is 2, so each vertex is an even vertex.
Since each vertex is even, this is a graph with four even vertices.