How is A a sufficient assumption? I didn't like any of the answer choices, so I pretty much guessed on this one. I thought A was the least attractive answer choice because it lacks the conditional nature that is typical for sufficient assumptions. My understanding of the argument is this:
We can't figure out how effective a certain model cleans simply be looking at how powerful the motor is. This is because the efficiency varies a lot, even with identical motors.
The sufficient assumption I was looking for was this: if efficiency varies (even with identical motor power), then we can't determine how effective the model cleans.
How does A paraphrase this?
