Darcy-Weisabach equation for loss of head in pipe is: -
Where f = friction factor, L = length, V = velocity m = A/P = area/wetted perimeter

A

$$f \left(\frac{L}{4m}\right).\left(\frac{V2}{2g}\right)$$

B

$$f \left(\frac{L}{m}\right).\left(\frac{V2}{2g}\right)$$

C

$$f \left(\frac{4L}{m}\right).\left(\frac{V2}{2g}\right)$$

D

$$f \left(\frac{4m}{L}\right).\left(\frac{V2}{2g}\right)$$