Question

david ma, an engineer at the university of hawaii in manoa, knew that its possible to generate electricity by creating friction, or rubbing two things together. so, he thought, \why dont we use water?\ what is david mas goal? to rub things together to make water to create friction by saving water to teach college students about water to generate electricity with water

Explanation:

The text states that David Ma knew electricity can be generated by creating friction (rubbing two things together) and then he thought about using water. So his goal is related to generating electricity with water. The first option is wrong as it says making water (not the case). The second option is wrong as saving water isn't the focus. The third option (teaching students) is not mentioned.

Answer:

To generate electricity with water