[求助]麻烦大家看看这道GWD逻辑啊~~~~~!!

Q40:

Which of the following most logically completes the argument?

Researchers recently asked dozens of shoppers, chosen at random coming out of a FoodBasket supermarket, what they had purchased.  The prices of the very same items at the nearest ShopperKing supermarket were totaled and compared with the FoodBasket total.  The ShopperKing totals averaged five percent higher than the FoodBasket totals.  Nevertheless, this result does not necessarily show that shoppers at ShopperKing would save money overall by shopping at FoodBasket instead, since ______.

1. shoppers who shop regularly at a given supermarket generally choose that store for the low prices offered on the items that they purchase most often
2. for shoppers with more than 20 items, the ShopperKing totals averaged more than five percent higher than the FoodBasket totals
3. many shoppers consider factors other than price in choosing the supermarket at which they shop most regularly
4. there is little variation from month to month in the overall quantity of purchases made at supermarkets by a given shopper
5. none of the people who conducted the research were employees of the FoodBasket supermarket

   Answer: A

-----------------------------------------------------------------------------------------------读懂了题意 但就没有明白A选项在这里什么意思

为什么A就说明shoppers at ShopperKing would 不一定save money overall by shopping at FoodBasket

谢谢指教啊~~~~

pls. be aware that:The ShopperKing totals averaged five percent higher ,  

total并不一定是说每件商品价格都低

读懂文章：

文章：问了从FB出来的人买了什么，并且比较了其中每一样东西和SK卖的价格，发现SK的平均价格高出5%

问：为什么这并不说明，在SK买东西的人只要选择去FB买东西，就会全面的省钱。

很简单，去FB买东西的人所买的东西，未必是那些在SK买东西的人要买的东西

举个例子：在FB买东西的人是买最低价的黄瓜，但是相应的黄瓜在SK卖的贵了5%，但是那些去SK的人并不是去买黄瓜的，而是去买西瓜的，那里的西瓜最便宜。

所以，那些要买西瓜的人去FB并不能省钱，相反，留在SK最好，因为那里最便宜。

消费目标不一致 So A is the answer