The Number of Cases of Flu Seen by Doctors at a County

Multiple Choice

The number of cases of flu seen by doctors at a county health clinic each week during a 10-week period is described by the quadratic function f ( x ) = -4 x ² + 40 x (graphed in the illustration) . What point gives us information of the most cases of flu?

A) (5, 100)
B) (8, 100)
C) (10, 0)
D) (5, 0)