A closely-coiled helical spring of stiffness k is cut into (n) equal parts. The stiffness in each part of the spring will be

• A. <i>k<span class="root">n</span></i>
• B. <i>n<span class="root">k</span></i>
• C. <i>nk</i>
• D. <i>nk</i>
• E. ²