Explanation:

- To find the cost of painting the walls, first calculate the area of the walls.

- The room is a square, with a perimeter of 230 m, so each side is 230/4 = 57.5 m.

- The total area of the four walls is perimeter × height: 230 × 5 = 1150 m².

- Cost of painting is Rs 7.50 per m².

- Total cost = 1150 m² × Rs 7.50 = Rs 8,625.

- Compare this with the options provided:

Option 1: Rs 4,312.50

Option 2: Rs 3,450

Option 3: Rs 8,625

Option 4: Rs 17,250