The length of a column which gives the same value of buckling load by Euler and Rankine-Gordon formula, is equal to

• A. <img src="/_files/images/civil-engineering/strength-of-materials/131-6.108-1.png">
• B. <img src="/_files/images/civil-engineering/strength-of-materials/131-6.108-2.png">
• C. <img src="/_files/images/civil-engineering/strength-of-materials/131-6.108-3.png">
• D. none of these.