If V1 and V2 are the velocities of water at inlet and outlet of the draft tube respectively, then the efficiency of a draft tube is

• A. <img src="/_files/images/mechanical-engineering/hydraulic-machines/195-46-1.png">
• B. <img src="/_files/images/mechanical-engineering/hydraulic-machines/195-46-2.png">
• C. <img src="/_files/images/mechanical-engineering/hydraulic-machines/195-46-3.png">
• D. <img src="/_files/images/mechanical-engineering/hydraulic-machines/195-46-4.png">