Answer:
Option (C)
Step-by-step explanation:
Gray water usually refers to water that are eliminated after the washing machine, bathtubs, and showers. These waters are drained in such a way that they do not come in contact with the feces. These are useful as they can be recycled and reuse. After recycling, this water can be used for irrigation purposes, washing clothes, and toilet flushing.
The use of this water helps in reducing the use of freshwater and saves a large amount of freshwater.
Thus, the correct answer is option (C).