The Profit P (In Thousands of Dollars) for a Company $P = - \frac { 1 } { 10 } s ^ { 3 } + 40 s ^ { 2 } + 1000$

Multiple Choice

The profit P (in thousands of dollars) for a company spending an amount s (in thousands of dollars) on advertising is $P = - \frac { 1 } { 10 } s ^ { 3 } + 40 s ^ { 2 } + 1000$ The point of diminishing returns is the point at which the rate of growth of the profit function begins to decline. Find the point of diminishing returns. Round your answer to the nearest thousand dollars.

A) 67 thousand dollars
B) 200 thousand dollars
C) 160 thousand dollars
D) 267 thousand dollars
E) 133 thousand dollars