请教一道问题

a year ago,Dietz Foods launched a yearlong advertising campaign for its canned tuna. Last year Dietz sold 12 million cans of tuna compared to the 10 million sold during the previous year, an increase directly attributable to new customers brought in by the campaign. Profit from the additional sales, however,were substantially less than the cost of the advertising campaign.Clearly, therefore, the campaign did nothing to further Dietz's economic interests.

b Most of the people who bought Diez's canned tuna for the first time as a result of the campaign were already loyal customers of other Dietz products 。

e In each of the past five years, there was a steep, industry-wide decline in sales of canned tuna.
    

这两个选项，我觉得b也能够为economic interests做出贡献。。。。但是答案是e 哪位牛人能帮忙解答一下。。谢谢

这题问的应该是削弱吧，楼主下次还是把题目说清楚一点

B 的话就是说这个广告其实没有吸引新的顾客，所以是在支持论点啊