2701. A close coil helical spring of mean diameter D consists of n coils of diameter d. If it carries an axial load W, the energy stored in the spring, is______________? September 7, 2025 by Admin A. 4WD²n/d4N B. 4W²Dn/d4N C. 4W²D3n/d4N D. 4W²D3n²/d4N ✅ The correct answer is option C.