If the K.E. of a body is increased by 300%, its momentum will increase by

The correct option is A

100%

Let initial kinetic energy, $E_1=E$

Final kinetic energy. $E_2=E+300$

As P $\infty \sqrt{E}\Rightarrow \frac{P_2}{P_1}=\sqrt{\frac{E_2}{E_1}}=\sqrt{\frac{4E}{E}}=2\Rightarrow P_2=2P_1$

$\Rightarrow P_2=P_1+100$

i.e. Momentum will increase by 100%.