So power is considered as the rate of doing work. Base on the problem given, my analysis is that the machine who finish the work faster is machine C. Therefore, in order to finish the same amount of work in a short period of time you are going to expend the most power. My answer is Machine C.
Answer:
Pish posh idk xD im busy but ill help in a second
Explanation:
This isn't physics, it's biology but basically, when you breath in oxygen, the oxygen goes to the lungs which transfer it to the blood cells. The heart then pumps the blood cells round to the organs, muscles etc and the blood cells drop off the oxygen where necessary, they then pick up carbon dioxide and the heart pumps them to the lungs where the blood cells give the lungs the carbon dioxide and the lungs make you breath the carbon dioxide out (his is a very simplified explanation, I'm not a biologist)
I think your best bet would be.
It acts in the direction opposite of the motion