Correct Answer: (a) It always finds the solution with the lowest total cost if the heuristic 'h' is admissible.
Solution:Optimality of the A* algorithm A search algorithm is optimal if no other search algorithm uses less time or space or expands fewer nodes both with a guarantee of solution quality. Optimality of A*–Among search algorithms that only use are costs and a heuristic estimate of the cost and a heuristic estimate of the cost from a node to a goal no algorithm expands fewer nodes. Then A* and guarantees to find a lowest-cost path. So option (a) is correct.