If the velocity of a body is doubled its kinetic energy:a. gets doubled b. becomes half c. does not change d. becomes 4 times

Because kinetic energy $K=\frac{1}{2}mv^2$, while $m\rightarrow$mass, $v\rightarrow$velocity.

If the velocity is doubled, the velocity becomes $2v$, therefore, kinetic energy $K'=\frac{1}{2}m(2v)^2=4\times\frac{1}{2}mv^2=4K$.

Therefore, the kinetic energy becomes 4 times.

So, option d is correct.