A cube has 6 equal square faces. Area of one face = 55 × 55 = 3025. Total surface area = 6 × 3025 = 18150 square m. Total surface area means the combined area of all outside faces. A cube has 6 equal square faces, so after finding one face area, multiply by 6. The answer is in square units, so the correct choice is 18150 m².