Susan Jahlberg, CFA recongnizes that the expanding economy of China is increasing prosperity and the demand for many types of goods and services. To estimate the demand for a particular item, which of the following elasticities of demand would be the best choice for Jahlberg to calculate?

price elasticity, income elasticity or cross-elasticity?

为什么答案选择income elasticity? 在估计某特特定商品的需求上，收入弹性有什么优势吗？谢谢解答。