A body is thrown vertically upwards from `A`. The top of a tower . It reaches the ground in time `t_(1)`. It it is thrown vertically downwards from `A` with the same speed it reaches the ground in time `t_(2)`, If it is allowed to fall freely from `A`. then the time it takes to reach the ground.

.

A. `t_(3) = (1)/(2) (t_(1)+t_(2))`

B. `t_(3)= sqrt(t_(1)t_(2))`

C. `(1)/(t_(3)) =(1)/(t_(2)) -(1)/(t_(1))`

D. `t_(3)^(2)=t_(1)^(2) -t_(2)^(2)`