If D is the diameter of upper circular portion, the area of cross-section of a standard egg shaped sewer, is

• A. <img src="/_files/images/civil-engineering/waste-water-engineering/183-9.58-1.png">
• B. <img src="/_files/images/civil-engineering/waste-water-engineering/183-9.58-2.png">
• C. <img src="/_files/images/civil-engineering/waste-water-engineering/183-9.58-3.png">
• D. <img src="/_files/images/civil-engineering/waste-water-engineering/183-9.58-4.png">