A Manufacturer Estimates That the Profit from Producing X Units $- x ^ { 2 } + 40 x - 100$

Multiple Choice

A manufacturer estimates that the profit from producing x units of a commodity is $- x ^ { 2 } + 40 x - 100$ dollars per week. What is the maximum profit he can realize in one week?

A) $300
B) $275
C) $500
D) $400
E) none of these