A car of mass m starts from rest and accelerates so that the instantaneous power delivered to the car has a constant magnitude P₀. The instantaneous velocity of this car is proportional to

• A

  ${\mathrm{t}}^{-1/2}$

• B

  $\frac{\mathrm{t}}{\sqrt{\mathrm{m}}}$

• C

  ${\mathrm{t}}^2{\mathrm{P}}_0$

• D

  t^{1 /2}