Who is Clark?

Clark is Billy’s best friend. Even though Billy believes Chrissie is the woman for him, Clark is the one who dances with her and walks her home the night they first met at the Buccaneer. Clark believes Chrissie stood him up when she did not show up for their date in the park the Sunday after they met. When he learns what had happened, Billy asks Chrissie to date him. He tells Clark he is dating Chrissie and Clark ends their friendship. They made amends only when Clark gets his call up papers for military service.