In 1992, a major newspaper circulated throughout North America paid its reporters an average salary that was much lower than the average salary paid by its principal competitors to their reporters. An executive of the newspaper argued that this practice was justified, since any shortfall that might exist in the reporters' salaries is fully compensated by the valuable training they receive through their assignments. Which one of the following, if true about the newspaper in 1992, most seriously undermines the justification offered by the executive? ['The circulation of the newspaper had recently reached a plateau, after it had increased steadily throughout the 1980s.', "Most of the newspaper's reporters had worked there for more than ten years.", "The union that represented reporters at the newspaper was different from the union that represented reporters at the newspaper's competitors.", 'The newspaper was widely read throughout continental Europe and Great Britain as well as North America.']