If g is a simple graph, its line graph l(g) is defined as follows: l(g) has one vertex for each edge in g, and two vertices of l(g) are adjacent if and only if the corresponding edges of g are adjacent. (a) draw l(c3), l(k3,1), l(k4) and l(w5). (b) assume that g is k-regular. show that l(g) is 2k – 2-regular.