A vessel of area of cross-section A has liquid to a height H . There is a hole at the bottom of vessel having area of cross-section a . The time taken to decrease the level from `H_(1)` to `H_(2)` will sec
A. `A/asqrt((2)/(g))[sqrt(H_(1)) - sqrt(H_(2))]`
B. `sqrt(2gh)`
C. `sqrt(2gh(H_(1) - H_(2))`
D. `A/asqrt((g)/(2))[sqrt(H_(1)) - sqrt(H_(2))`