Water (density: 1000 kgm-3) stored in a cylindrical drum of diameter r1 m is emptied through a horizontal pipe of diameter 0.05 m. A pitot-static tube is placed inside the pipe facing the flow. At the time when the difference between the stagnation and static pressures measured by the pitot-static tubes is 10 kPa, the rate of reduction in water level int eh drum is,

• A. \(\frac{1}{{200\sqrt 5 }}m{s^{ - 1}}\)
• B. \(\frac{1}{{75\sqrt {10} }}m{s^{ - 1}}\)
• C. \(\frac{1}{{50\sqrt {10} }}m{s^{ - 1}}\)
• D. \(\frac{1}{{40\sqrt 5 }}m{s^{ - 1}}\)