If the rate of change of grade permitted along a vertical curve is r and total change of grade is g%, the length L of the curve to be provided, is

• A. <img src="/_files/images/civil-engineering/highway-engineering/33-16-115-1.png">
• B. <img src="/_files/images/civil-engineering/highway-engineering/33-16-115-2.png">
• C. <img src="/_files/images/civil-engineering/highway-engineering/33-16-115-3.png">
• D. <img src="/_files/images/civil-engineering/highway-engineering/33-16-115-4.png">
• E. none of these.