Correct Answer  Option 2 : 8 Kgm/s
CONCEPT:

Momentum: A property of a body in motion that is equal to the product of the body's mass and velocity is called momentum.
P = mv
where P is the momentum of the body, m is the mass of the body, and v is the velocity of the body.

Kinetic energy: The energy in a body due to its motion, is known as kinetic energy.
The kinetic energy in terms of momentum is given by:
\(K=\frac{P^2}{2m}\)
where K is the kinetic energy of the body, P is the momentum of the body and m is the mass of the body.
CALCULATION:
Given that the Kinetic energy of the body = 8 J, m = 4 kg
\(K=\frac{P^2}{2m}\)
\(8=\frac{P^2}{2 \times 4}\)
P = 8 Kgm/s
So the correct answer is option 2.