In the quadratic regression screen shown in the problem statement, why is the value of the coefficient a negative? A. Since the height increases then decreases, the quadratic graph must open downward, not upward, which means a must be negative. B. Since the height of the ball starts at the height of the person throwing the ball, the quadratic graph must be shifted up, which makes a negative. C. Since the height increases then decreases, the quadratic graph must open upward, not downward, which means a must be negative