If the Total Revenue Function for a Blender Is $R ( x ) = 40 x - 0.25 x ^ { 2 },$

Multiple Choice

If the total revenue function for a blender is $R ( x ) = 40 x - 0.25 x ^ { 2 },$ find the maximum revenue.

A) $80
B) $1500
C) $40
D) $100
E) $1600