Consider the below initial and goal states (three equally acceptable goals are given) of a planning problem and answer the follo below in questions. In this problem the agent can move any labelled tile on top of other labelled tiles or on top of the empty tile (colored gi [2+3+3+2 = 10 Marks] Initial State B A D Goal State - 1 Goal State-2 Goal State - 3 B D A B D B D A (a) Define a best suitable heuristic to design the cost function and justify your choice