Correct Answer - A
Aa no external torque acts on the system, angular moemtum should be conserved. Hence, `I omega=constant`....(i)
Where `,I` is moment of inertia of the system and ` omega` is angular velocity of the system
From eq. (i) `I_(1)omega_(1)=I_(2)omega_(2)`
(where `omega_(1)` and `omega_(2)` are angular velocities before and after jumping)
`rArrI omega=I/2 xxomega_(2)`
(as mass reduce to half, hence, moment of inertia also reduced to half)
`Iomega_(2)=2 omega`