A Firm Is Producing Two Goods X and Y)that Are

A firm is producing two goods X and Y) that are related in consumption.The demand function for X is: Which of the following pairs of goods might the firm be producing?

A) cars and gasoline
B) cola and caffeine-free coke
C) newspapers and tennis balls
D) bran cereal and sugar-frosted corn flakes
E) both b and d