Statement $-1-$ If there is no external torque on a body about its centre of mass, then the velocity of the centre of mass remains constant. Statement $-2-$ The Linear momentum of an isolated system remains constant.
$\{\mathrm{A}\}$ Statement $-1$ is correct (true), Statement $-2$ is true and Statement- 2 is correct explanation for Statement - 1
$\{B\}$ Statement $-1$ is true, statement $-2$ is true but statement $-2$ is not the correct explanation four statement $-1$.
$\{\mathrm{C}\}$ Statement $-1$ is true, statement- 2 is false
\{D $\}$ Statement- 2 is false, statement $-2$ is true