[单选题]
A ball is thrown with a velocity of 20 m/s at an angle oy:1mq47kt ip5 8 5 9eiprgf9f kqu(yxhf 60e abid4q; h g6b7mhzm3vs )b;9broove the horizontal. What is the h zsqi)b7b m43bvh9gd6 o;hr;m orizontal component of its instantaneous velocity at the exact top of its trajectory?
