A cube has 6 equal square faces. Area of one face = 41 × 41 = 1681. Total surface area = 6 × 1681 = 10086 square mm. 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 10086 mm².