A pipe consisting of several pipes of varying diameters and lengths, may be replaced by an equivalent pipe of diameter D of length

• A. <img src="/_files/images/civil-engineering/hydraulics/153-7.163-1.png">
• B. <img src="/_files/images/civil-engineering/hydraulics/153-7.163-2.png">
• C. <img src="/_files/images/civil-engineering/hydraulics/153-7.163-3.png">
• D. <img src="/_files/images/civil-engineering/hydraulics/153-7.163-4.png">