_ Coefficient of contraction is the ratio of$?

• A. Actual velocity of jet at vena contracta to the theoretical velocity
• B. Loss of head in the orifice to the head of water available at the exit of the orifice
• C. Loss of head in the orifice to the head of water available at the exit of the orifice
• D. Area of jet at vena-contracta to the area of orifice