The correct option is A P=√2mE
Lets take,
m= mass of a body
v= velocity of body
We know that kinetic energy is given by the formula, E=12mv2 ...(i)
The momentum is given by the formula, P=mv ...(ii)
In equation (i), multiply and divide by m(mass) we get,
E=12mv2×mm=P22m as, (P=mv)
⇒P2=2mE
P=√2mE,
Hence option A is the correct answer.