The area of cross section of the wider tube shown in figure is $900cm^2$.If the boy standing on the piston weights 45Kg then difference in the levels of water in the two tubes are ($\rho_{water}=1000Kg/m^3)$

Question

$\begin{array}{1 1}(A)\;60cm\\(B)\;52cm\\(C)\;50cm\\(D)\;45cm\end{array}$