Correct Answer - C
`H=(u^(2))/(2g)`, given `v_(2)=2v_(1)` (i)
`A` to `B`: `v_(1)^(2) =u^(2)-2 g t` (ii)
`A` to `C`: `v_(2)^(2)=u^(2)-2g (-h)` (iii)
Solving (i) ,(ii) and (iii), we get the value `u^(2)` as `10gh//3 ` and then we get the value of `H` by using

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`H= (u^(2))/(2g)`.