Answer:
The answer is D.
Explanation:
Look at these options. Do all of these require effort? Yes. If you were to push a shopping cart, do you have to apply force? if you were to lift a book, do you indeed move the book, does it exert force? While walking up stairs, do you have to move your legs uphill, is there force used? All of these require input, and force. Most things in life require work, unless we have a machine to do it for us.
