求解一道新东方讲义上的题，望帮忙

corrine90

Sales of telephones have increased dramatically over the last year. In order to take advantage of this increase, Mammoth plans to expend production of its own model of telephone, while continuing its already very extensive advertising of this product.
Which of the following, if true, provides most support for the view that Mammoth cannot increase its sales of telephones by adopting the plan outlined above?
A.Although it sells all of the telephones it produces,Mammoth's share of all telephones sales has declined over the last year.
B.Mammoth's average inventory of telephones awaiting shipment to retailers has declined slightly over the last year.
C.Advertising has made the brand name of Mammoth's telephones widely known, but few consumers known that the Mammoth owns this brand.
D.Mammoth's telephone is one of the three brands of telephone that have together accounted for the bulk of the last year's increaase in sales.
E.Despite a slight decline in the retail price, sales of Mammoth's telephons haave fallen in the last year.
讲义给的答案是E，但我选了D，其它选项排的也很辛苦。。。望牛人讲解下，谢谢

corrine90

是哪版OG呀？找来OG解释来看看~~