A vertex cover of a graph G = (V,E) is a subset of vertices V ∈ V such that every edge in E contains at least one vertex from V . An independent set of graph G = (V,E) is a subset of vertices V ∈ V such that no edge in E contains both vertices from V . An independent vertex cover is a subset of vertices that is both an independent set and a vertex cover of G. Give an efficient algorithm for testing whether G contains an independent vertex cover. What classical graph problem does this reduce to?