The length of pipe is L, velocity of flow of a liquid in the pipe is V. If t is the time in second required to close the valve, the head of pressure

• A. <img src="/_files/images/civil-engineering/hydraulics/162-7.276-1.png">
• B. <img src="/_files/images/civil-engineering/hydraulics/162-7.276-2.png">
• C. <img src="/_files/images/civil-engineering/hydraulics/162-7.276-3.png">
• D. none of these.