The ratio of the hydraulic radius of a pipe running full to the hydraulic radius of a square section of a channel whose side is equal to the diameter of the pipe, is

• A. 1
• B. <img src="/_files/images/civil-engineering/hydraulics/56-3.94-2.png">
• C. <img src="/_files/images/civil-engineering/hydraulics/56-3.94-1.png">
• D. <img src="/_files/images/civil-engineering/hydraulics/56-3.94-6.png">