Answer: A decrease in the price of one will increase the demand for the other.
Explanation:Two goods are said to be complementary if there is an increase in the demand of the good due to increased growth or popularity of the other.
For example goods B and C are complements if there is an increase in the the demand of good B when the price of good C decreases or if there is a decrease in the demand of good B when the price of good C increases and vice versa. These shows that both goods complement each other and as such a negative or positive impact on the popularity or growth of one will result in a corresponding negative or positive demand of the other.
