Explanation

(c) Two masses are moving with equal kinetic energy.
$\frac{1}{2}Mv_{1}^{2} = \frac{1}{2}4Mv_{2}^{2}$
$or\ \ \frac{{\ v}_{1}}{v_{2}} = 2$
The ratio of linear momentum is
$\frac{p_{1}}{p_{2}} = \frac{Mv_{1}}{4Mv_{2}}$
$or\ \frac{p_{1}}{p_{2}} = \frac{1}{4}\left( \frac{v_{1}}{v_{2}} \right)$
$or\ \frac{p_{1}}{p_{2}} = \frac{2}{4} = \frac{1}{2}$
$or\ \ p_{1}:p_{2} = 1:2$