Which statement weakens the author's claim that schools should require students to participate in sports? A. The spirit of sportsmanship can help one build good relations with people and go a long way in life. B. So, parents are obviously wrong and need to do more research. C. Nowadays, children experience a sedentary lifestyle as they mostly remain indoors with their laptops or mobile phones. D. Therefore, it is very important that children learn to balance their studies and sports.