c.many shoppers consider factors other than price in choosing the supermarket at which they shop most regularly.c不是必然原因,选项并没有之处除了价格外的因素是什么因素,如果不关钱的事呢?比方有些顾客爱享受,他favor购物环境好的或者服务好的,那么与文中的原因就构不成关系了~~所以与原因关系最直接的还是a
the correct answer is more likely to be E. Because in the United States if you are an employee of Depratment store, you are naturally have the benefit of discount, namly if you buy stuff from the store where you are working, you can get usually 40% price discount of the stuff. So bcause no people who are surveyed are employee of B, so that means some of the persons who was surveyed are employees of S. So this assumption can help to support the conclusion.