The correct answer is: C. The good is a substitute.
Cross elasticity of demand measures the responsiveness of the demand for one good to a change in the price of another good. A large positive cross elasticity of demand indicates that the two goods are substitutes, meaning that they can be used interchangeably. For example, if the price of coffee increases, people may be more likely to drink tea instead. This would lead to an increase in the demand for tea, and a decrease in the demand for coffee.
A normal good is a good whose demand increases when income increases. An inferior good is a good whose demand decreases when income increases. A complement is a good that is used together with another good. For example, cars and gasoline are complements, because people are more likely to buy cars if gasoline is cheap.
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