Suppose the path of a baseball follows the path graphed by the quadratic function f(d)=-0.6d^2+5.4d+0.8 where d is the horizontal distance the ball traveled in yards, and f(d) is the height, in the yards, of the ball at d horizontal yards. Find the intail height of the ball?
A. 0.6 yards
B. 5.4 yards
C. 0.8 yards
D 0.94 yards