Final answer:
The statement is true. If the cross price elasticity of demand is negative, then the two goods under consideration must be complements.
Step-by-step explanation:
The statement is true. If the cross price elasticity of demand is negative, it means that a decrease in the price of one good leads to an increase in the quantity demanded of another good.
Complement goods are goods that are typically consumed together, such as coffee and sugar. When the price of sugar increases, people tend to consume less sugar, which will decrease the demand for sugar and also decrease the demand for other goods that are typically consumed with sugar, like coffee. Therefore, a higher price for sugar results in a decrease in the quantity demanded of coffee, indicating a negative cross-price elasticity of demand and confirming that the two goods are complements.