The correct answer is C. It does not affect your level of physical activity.
It does also lower your risk of injury as using the correct tools for any job is important and makes the job easier and you are less likely to have an injury of you know how to use the tool properly.
However in this case the answer is C. You are expending energy as you are using muscles and force to use the screwdriver but you are not increasing your level of physical activity.
