-The Demand Function for a Certain Make of Replacement Cartridges

Multiple Choice

-The demand function for a certain make of replacement cartridges for a water purifier is given by ​ ​
Where p is the unit price in dollars and x is the quantity demanded each week, measured in units of a thousand. Determine the consumers' surplus if the market price is set at $1/cartridge. Round your answer to the nearest dollar.
​

A) $22,006
B) $21,526
C) $21,445
D) $21,667