(单选题)

What is the purpose of the first letter? ( )

A.To point out a mistake on an invoice.

B.To complain about a late delivery.

C.To show appreciation for good service.

D.To inquire about a product on sale.

参考答案：A

参考解析：

根据I received the bill for my August account on September 5, 2018, and was very surprised to find that I had been charged for a box of diapers I didn't buy.可知第一封邮件是在说账单出了问题。选项A：指出发票清单错误，表达符合文意；选项B：抱怨货物送迟了，文中并未提及；选项C：对服务的赞赏，属于无中生有；选项D：询问物品价格，文中未提及。故本题正确答案选A。

知识点：主旨题英语阅读理解通用英语