Suppose that the cross-price elasticity of the demand for beer with respect to the price of wine is +0.30 in Sweeden, but -0.25 in Luxemborg. Which of the following is true:
a. Wine is a complement for wine in Sweeden and Luxemborg
b. Wine is a substitute for wine in Sweeden and Luxemborg
c. Wine is a complement for wine in Sweeden and a substitute in Luxemborg
d. Wine is a substitute for wine in Sweeden and a complement in Luxemborg