Last Month,sellers of Good Y Took in $100 in Total

Multiple Choice

Last month,sellers of good Y took in $100 in total revenue on sales of 50 units of good Y.This month sellers of good Y raised their price and took in $120 in total revenue on sales of 40 units of good Y.At the same time,the price of good X stayed the same,but sales of good X increased from 20 units to 40 units.We can conclude that goods X and Y are

A) substitutes,and have a cross-price elasticity of 0.60.
B) complements,and have a cross-price elasticity of -0.60.
C) substitutes,and have a cross-price elasticity of 1.67.
D) complements,and have a cross-price elasticity of -1.67.