The expression for the slenderness Ratio ratio of the columns is given as ________.

A

$$\left(\frac{l_e}{K_{min}}\right)^2$$

B

$$\left(\frac{2l_e}{K_{min}}\right)^2$$

C

$$\left(\frac{l_e}{K_{min}}\right)$$

D

$$\left(\frac{2l_e}{K_{min}}\right)$$