If a1 and a2 are the cross-sectional areas of a tank and orifice, h the height of water level in tank above the centre of the orifice, the velocity of approach is given by

• A. <img src="/_files/images/civil-engineering/hydraulics/150-7.120-1.png">
• B. <img src="/_files/images/civil-engineering/hydraulics/150-7.120-2.png">
• C. <img src="/_files/images/civil-engineering/hydraulics/150-7.120-3.png">
• D. <img src="/_files/images/civil-engineering/hydraulics/150-7.120-4.png">