If a vessel containing a fluid of density $\rho$ up to height $h$ is accelerated vertically downwards with acceleration $a_0$,then the pressure by the fluid at the bottom of the vessel is given by the equation ........ ($p_0$ denotes the atmospheric pressure and $g$ denotes the acceleration due to gravity).

• A
  $p=p_0+\rho g h+\rho h a_0$
• B
  $p=p_0+\rho g h$
• C
  $p=p_0+\rho h(g-a_0)$
• D
  $p=p_0-\rho g h$