Exercise 7.

Which of the graphs below are bipartite? Justify your answers.

A graph with five vertices. Four vertices make up the corners of a diamond; the last vertex is in the center. Edges form the perimeter of the diamond and connect the center vertex to the two corners on the left and right.
A graph consisting of six vertices arranged in a hexagon. Edges connect each vertex to two others, but not in a cycle around the outside of the hexagon. However, following along the edges does visit every vertex.
A graph consisting of seven vertices arranged in a seven-sided polygon, with edges forming the perimeter of the polygon.
A graph consisting of a single vertex with eight edges connecting to eight vertices arranged in a circle around the central vertex.
Hint.
in-context