Hello,
Here is your answer:
The proper answer to this question is option A "Repairing leaky faucets". That's because a water conversation technique is how you can preserve water without wasting to much. B, C, and D your using a lot of water.
Your answer is A.
If you need anymore help feel free to ask me!
Hope this helps!
Acidity.
If it has less acid it is considered an alkaline
If it has more acid it is acidic