Last year a large firm set a goal of decreasing its workforce by 25 percent. Three divisions, totaling 25 percent of its workforce at that time, were to be eliminated and no new people hired. These divisions have since been eliminated and no new people have joined the firm, but its workforce has decreased by only 15 percent. Which one of the following, if true, contributes most to an explanation of the difference in the planned versus the actual reduction in the workforce? ['Some of the employees in the eliminated divisions were eligible for early retirement and chose that option.', 'The three divisions that were eliminated were well run and had the potential to earn profits.', 'Normal attrition in the retained divisions continued to reduce staff because no new people were added to the firm.', 'As the divisions were being eliminated some of their employees were assigned to other divisions.']