请教两道题

12.   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.

我选D，答案是E，请问两个选项的区别？

20.   For a local government to outlaw all strikes by its workers is a costly mistake, because all its labor disputes must then be settled by binding arbitration, without any negotiated public-sector labor settlements guiding the arbitrators. Strikes should be outlawed only for categories of public-sector workers for whose services no acceptable substitute exists.

The statements above best support which of the following conclusions?

(A) Where public-service workers are permitted to strike, contract negotiations with those workers are typically settled without a strike.

(B) Where strikes by all categories of pubic-sector workers are outlawed, no acceptable substitutes for the services provided by any of those workers are available.

(C) Binding arbitration tends to be more advantageous for public-service workers where it is the only available means of settling labor disputes with such workers.

(D) Most categories of public-sector workers have no counterparts in the private sector

(E) A strike by workers in a local government is unlikely to be settled without help from an arbitrator.

为何选C，如何推出？

12 This is OG 28 , checking the OG explanation will be better !!