A cyclinderical vessel of cross-sectional area `1000cm^(2)`, fitted with a frictonless piston of mass `10kg`, and filled with water completely. A small hole of cross-sectional area `10mm^(2)` is opened at a point `50cm` deep from the lower surface of the piston. The velocity of efflux from the hole will be
A. `10.5m//s`
B. `3.4m//s`
C. `0.8m//s`
D. `0.2m//s`
