In a baro meter as shown in the figure a small hole is made at a point S Density of mercury is $\rho$. The mercury comes out from this hole with speed v equal to

Question

$\begin{array}{1 1} (a)\;\sqrt {2gh} \\ \\ (b)\;\sqrt {2gH} \\ (c)\;\sqrt {2g(H-h)} \\ (d)\;none\;of\;these \end{array}$