Either draw a graph or tree with the given specifications or

Either draw a graph or tree with the given specifications or explain why no such graph or tree exists?

(a) Graph, circuit free, seven vertices, four edges

(b)Tree, twelve vertices, fifteen edges

(c) Tree, ten vertices, total degree 24

(d) Simple graph, six vertices having degrees 1,2, 3, 4, 5, 5

Solution