问题
单项选择题
Income elasticity is defined as the:（）
A. percentage change in income divided by the percentage change in the quantity demanded.
B. change in quantity demanded divided by the change in income.
C. percentage change in the quantity demanded divided by the percentage change in income.
答案
参考答案：C
解析：
Income elasticity is defined as the percentage change in quantity demanded divided by the percentage change in income. Normal goods have positive values for income elasticity and inferior goods have negative income elasticities.