Your On-Line Bookstore Is in Direct Competition with Amazon $R ( x , y , z ) = 25,000 - 0.02 x - 0.02 y - 0.01 z + 0.00005 y z$

Multiple Choice

Your on-line bookstore is in direct competition with Amazon.com, BN.com, and Borders.com. Your company's daily revenue in dollars is given by $R ( x , y , z ) = 25,000 - 0.02 x - 0.02 y - 0.01 z + 0.00005 y z$
Where x, y, and z are the online daily revenues of Amazon.com, BN.com, and Borders.com, respectively. If Amazon.com and BN.com each show a daily revenue of $1,000, give an equation showing how your daily revenue depends on that of Borders.com.

A) R (z) = 24,960 + 0.04z
B) R (z) = 25,000 - 20x - 20y - 0.01z + 0.00005yz
C) R (z) = 25,000 - 0.01z
D) R (z) = 24,960
E) R (z) = 25,000 - 0.01z + 0.00005z