You are given a sentence and a question. You're expected to write the correct answer based on the sentence.

Let me give you an example: Sentence: Jacob and Benny are squatting at the gym. Jacob has thin frail legs and Benny has big strong legs. Question: Who squats less weight?
The answer to this example can be: Jacob
Here is why: Typically, people with thin frail legs squat less weight than people with big strong legs, so the answer is Jacob.

OK. solve this:
Sentence: A dog toy thrown across a grassy field travels at a lower rate of speed compared to one thrown across a dirt field. Question: Which field is the least rough?
Answer:
dirt field