Answer:
C. To inform
Explanation:
To inform because they aren't trying to sell anything they are telling what there solution is to that problem.
It shows you team work, temptations, hard work,etc.
If the root hydro- means "water", then the word that means "an electrical instrument used to monitor underwater sounds" is called a hydrophone. A hydrophone is a kind of microphone that is specifically used to detect and record sound waves underwater.
