A U-tube having horizontal arm of length 20 cm, has uniform cross-sectional area`=1cm^(2)`, It is filled with water of volume 60 cc. What volume of a liquid of density `4g//cc` should be poured from one side into the U-tube so that no water is left in the horizontal arm of the tube?
A. `60c c`
B. `45c c`
C. `50c c`
D. `35c c`
