The displacement x of a particle varies with time as
$\mathrm{x}={\mathrm{ae}}^{-\mathrm{\alpha t}}+{\mathrm{be}}^{\mathrm{\beta t}}$
where e, b, o and F are positive constants.
The velocity of the particle will

• A

  go on decreasing with time

• B

  go on increasing with time

• C

  be independent of $\mathrm{\alpha }$ and $\mathrm{\beta }$

• D

  drop to zero when  $\mathrm{\alpha }$ = $\mathrm{\beta }$