At the edge of a roof you throw ball 1 upward with an initial speed v0; a moment later you throw ball 2 downward with the same initial speed. The balls land at the same time. Which of the following statements is true for the instant just before the balls hit the ground? A. The speed of ball 1 is greater than the speed of ball 2; B. The speed of ball 1 is equal to the speed of ball 2; C. The speed of ball 1 is less than the speed of ball 2.