单选题 A well-known former quarterback is probably very adept at analyzing the relative strengths of football teams. However, efforts by television advertisers to suggest that the quarterback is an expert on pantyhose or popcorn poppers should arouse skepticism among viewers. The same response should result when a popular television actor, who is frequently cast in the role of a doctor, appears in a commercial to endorse a brand of decaffeinated coffee. His views on televisior acting would deserve attention since he has had considerable experience in that field, but viewers have every right to doubt his authority in coffee advertisements.
Which one of the following is a presupposition essential to the reasoning in the passage above?

A、 The strength of authoritative evidence as legitimate proof is closely related to the authority's degree of expertness in the area in question.
B、 Practical experience counts for more than academic training in assessing the competence of authorities.
C、 The only kind of evidence being used in many television commercials is appeal to authority.
D、 The viewing audience is not sufficiently capable of evaluating authoritative appeals in advertisements.
E、 (E) Television viewers will somehow mentally transfer the credibility of celebrities in one area of expertise to another represented by the product being advertised.

【正确答案】 A

【答案解析】[解析] 由本题所列举的两个关于足球队员及男演员的例子可以看出权威人士只有在他们自身的专业领域内发表见解时才能得到听众的认可，由此可知(A)是本题的论证所依赖的前提；(B)、(C)、(D)和(E)都是无关选项。
quarterback n. (美式足球)四分卫，进攻时指挥本队的选手。