Okada Cleaning Service is offering discounts this month as a special ______ for customers who refer their friends.

【正确答案】 A

【答案解析】 A项意为“报酬”，符合题意；B、D两项均为“动机”之意，C项意为“原因”，均与题意不符。句意为“Okada清洁公司这个月为邀请朋友的顾客提供打折，作为特别的报酬”。