The editorial departments of both newspapers A and B have staff who specialize in proofreading. Last year, there were some typographical errors in newspaper A. while newspaper B had no typographical errors. Therefore, in the proofreading work of last year, the proofreading of newspaper B Clerks work more effectively than newspapers' proofreaders. The above conclusion is based on the assumption that. ['Newspaper copywriters work longer than newspaper copywriters.', 'The number of typographical errors received by newspaper A is no less than that of newspaper B.', 'Newspaper A has fewer pages per issue than Newspaper B.', "The number of typographical errors is the criterion for evaluating the effectiveness of the proofreader's work."]