Given that g = acceleration due to gravity and R = hydraulic mean depth, the Darcy Weisbach friction factor is related to Manning's rugosity coefficient 'n' as

• A. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/07-642-1.png">
• B. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/07-642-2.png">
• C. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/07-642-3.png">
• D. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/07-642-4.png">