OG-28，请答疑，谢谢

28. Fact 1: Television advertising is becoming less effective: the proportion of brand names promoted on
television that viewers of the advertising can recall is slowly decreasing.
Fact 2: Television viewers recall commercials aired first or last in a cluster of consecutive commercials far better
than they recall commercials aired somewhere in the middle.
Fact 2 would be most likely to contribute to an explanation of fact 1 if which of the following were also true?
A. The average television viewer currently recalls fewer than half the brand names promoted in commercials
he or she saw.
B. The total time allotted to the average cluster of consecutive television commercials is decreasing.
C. The average number of hours per day that people spend watching television is decreasing.
D. The average number of clusters of consecutive commercials per hour of television is increasing.
E. The average number of television commercials in a cluster of consecutive commercials is increasing.

答案是E，偶实在是不明白，E的意思有将一串广告按比例的分开吗？我觉得还不如D有说服性。
请指点，谢谢