题目选项分析

At Funston Stores, a salesperson's salary is comprised solely of commissions from sales. A particular salesperson's annual salary was lower in 2009 than in 2008. In both years, all of this salesperson's sales were of only one item, product X, and he made the same number of product X sales in both years. The commission percentage for all Funston salespeople has remained unchanged over the past ten years.

The information above most strongly supports which of the following?

【选项】Through all of Funston Stores, the overall number of sales of product X declined from 2008 to 2009