Microsoft has a special version of its Windows operating system that it sells at a low price in countries where cheap pirated software is widespread. The cost of producing another copy of this software is the same as the cost of producing another copy of the regular Windows product. Selling this "special edition" software at a low price in certain countries is very similar to what economists call:_______
a) welfare loss.
b) natural monopoly.
c) a price taker.
d) price discrimination.