Hydraulic efficiency of Francis turbine is

• A. Directly proportional to velocity of whirl at inlet and inversely proportional to net head on turbine
• B. Directly proportional to velocity of whirl at inlet and net head on turbine
• C. Inversely proportional to velocity of whirl at inlet and net bead on turbine
• D. Inversely proportional to velocity of whirl at inlet and directly proportional to net head on turbine