A cube has 6 equal square faces. Area of one face = 45 × 45 = 2025. Total surface area = 6 × 2025 = 12150 square cm. 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 12150 cm².