A ball is thrown upward at an angle of 45° with the horizontal and lands on the top edge of a building that is 20 m away. The top edge is 10m above the throwing point. The initial speed of the ball in metre/second is (take g = 10 m/s2 ) :
(A) 10 m/s
(B) 20 m/s
(C) 25 m/s
(D) 30 m/s
