If U and V are the velocities of water at two points in a pipe line, the difference in pressure energy to water is P =

A. $$\frac{{{{\text{V}}^2}}}{{2{\text{g}}}} + \frac{{{{\text{U}}^2}}}{{2{\text{g}}}}$$

B. $$\frac{{{{\text{V}}^2}}}{{2{\text{g}}}} - \frac{{{{\text{U}}^2}}}{{2{\text{g}}}}$$

C. $$\frac{{{{\text{V}}^2}}}{{\text{g}}} - \frac{{{{\text{U}}^2}}}{{\text{g}}}$$

D. $$\frac{{{{\text{V}}^2} - {{\text{U}}^2}}}{{3{\text{g}}}}$$

Answer: Option B