20.A 5-kg cat accidentally drops from a building with 60 m in height. Based on the natural response, the cat stretches the limbs to maximize its body area. Assume the body area perpendicular to the direction of gravity is 800 cm², the air density is 1.2 kg/m³ and the drag coefficient is 1, at what height above the ground the cat can reach its terminal velocity?(A) 8 m (B) 9 m (C) 13m (D) 20 m