4. [2+4+4+4]Consider the search space below, where S is the start node and G1 and G2 satisfy the goal test. Arcs are labeled with the cost of traversing them and the estimated cost to a goal is reported inside nodes (so lower scores are better) G2 GI a) Would it be a good idea to use the Depth-First Search in this example or not? Why? Write the contents of the frontier, putting the path that will be selected as the first element, for four iterations using b) lowest-cost first c) best-first d) A*