Consider the following graph on vertices a to j, where for each vertex, outgoing edges are listed: a: b, c . b: c, . c: d, i . d: e, j e: f: g, j i: f How many different topological orderings are there for the vertices of this graph? Consider the following graph on vertices a to j, where for each vertex, outgoing edges are listed: a: b, c . b: c, . c: d, i . d: e, j e: f: g, j i: f How many different topological orderings are there for the vertices of this graph