function GRAPH-SEARCH(problem, fringe) closed ? empty set fringe ? INSERT(MAKE-NODE(INITIAL-STATE[problem]), fringe) loop if fringe is empty then return failure end if nodeR IF GOAL-TEST(problem,STATE[node]) THEN REMOVE-FRONT(fringe) RETURN node END IF ADD STATE[node] TO closed fringe ? INSERTALL(EXPAND(node, problem), fringe) END LOOP END FUNCTION Circle all that apply: (a) Nodes may be expanded twice. b) The algorithm is not complete. (c) The algorithm could return an incorrect solution (d) None of the above