WHY DOES THE AUTHOR MENTION A CHINESE TOY

59. - File thứ 1: De va dap an thi thu lan 2, Anh
Tiếng Anh File thứ 1: De va dap an thi thu lan 2, Anh
59. Why does the author mention a Chinese toy? A. To contrast helicopters and fixed wing aircraft. B. To show that helicopter flight was envisioned in ancient times. C. To prove that helicopters were the first aircraft. D. To emphasize to complex design of helicopters.