Explain the concept of head loss and why it matters in network design.

• A. Head loss is a decrease in pipe diameter over distance; it affects color of water.
• B. Head loss is the energy gained due to turbulence; it reduces pumping needs.
• C. Head loss is energy loss due to friction as water flows; it affects pumping needs, reservoir sizing, and pressure at nodes.
• D. Head loss is the loss of water volume due to evaporation.

Answer: (C)