弱問排除他因是甚麼意思

A
year ago, Dietz Food launched a yearlong advertising campaign for its
canned tuna. Last year, Dietz sold 12 million cans of customers brought
in by the campaign. Profits form the additional sales, however, were
substantially less than the cost of the advertising campaign. Clearly,
therefore, campaign did nothing to further Dietz food economic
interests.

A. Sales of canned tuna account for a relatively small percentage of Dietz Food’s profit.

B.
Most of the people who bought Diefdtz’s canned tuna for the first time
as a result of the campaign were already loyal customers of other Dietz
products.

C.
A less expensive advertising campaign would brought in significantly
fewer new customers for Dietz’s canned tuna did the campaign Dietz’s
launched last year.

D. Dietz made money on sales of canned tuna last year.

E. In each of the past five years, there was a steep. Industry-wide declines in sales of canned tuna.

答案是E且E為排除他因

在這題中的"其他原因"是甚麼呢