And is BCD,I didn't get option C please help

Q.11 Pressure difference between the top and bottom surface of the liquid placed in a cylindrical which is accelerating downwards with constant acceleration a is

$$\begin{gathered} \left(A\right) \rho \left(g-a\right)h \\ \left(B\right) \rho \left(g-a\right)h if a<g \\ \left(C\right) Zero if a>g \\ \left(D\right) Zero if a=g \end{gathered}$$