Consider a collection of circles (of varying sizes) in the plane. Make a 'circle graph' with a vertex for each circle and an edge between two vertices when they correspond to two circles that cross (if one circle properly contains another, there would be no edge). a) Draw a family of circles whose circle graph is 5-chromatic (requires 5 colors to properly color). b) Draw a family of circles whose circle graph has neither a Hamilton nor Euler circuit. c) Draw a family of circles whose circle graph is a K3,3