Answer:
B
Step-by-step explanation:
The efficient use of water through plumbing saves water by preventing leaking, with correct piping and at a due flow rate. Efficient plumbing also collects rainwater to its system, so that the waste can be minimized.
It all starts with an optimized design that values correct angles, appropriate length. The aim is providing zero water waste, reduce energy consumption.
A plumbing system like this is also called the Green Plumbing System.