The correct answer is D.
The text states that "The same pattern emerged. The amateurs never practiced more than about three hours a week over the course of their childhood, and by the age of twenty
they had totaled two thousand hours of practice." This passage supports the answer to Question 5, which is "Amateurs practice less than professionals." The passage states that the amateurs never practiced more than three hours a week, while the professionals practiced much more. This suggests that amateurs practice less than professionals.