4. 12+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 G1 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*