Correct Answer - A
`s_(2)=1/2g(2xx2-1)=(3g)/2 `
`s_(3)=1/2g(2xx3-1)=(5g)/2`
`s_(4)=1/2g(2xx4-1)=(7g)/2`
`s_(2):s_(3):s_(4)=3:5:7`
Note: If a particle is moving in a straight line under constant acceleration//deceleration, the displacement of particle in successive time interval is in the ratio of odd numbers.