GWD5-21.请教了，谢谢

An overwhelming proportion of the most productive employees
at SaleCo’s regional offices work not eight hours a day, five days a week, as
do other SaleCo employees, but rather ten hours a day, four days a week, with
Friday off.  Noting this phenomenon,
SaleCo’s president plans to increase overall productivity by keeping the
offices closed on Fridays and having all employees work the same schedule—ten
hours a day, four days a week.

Which of the following, if true, provides the most reason to
doubt that the president’s plan, if implemented, will achieve its stated purpose?

1. Typically,
        a SaleCo employee’s least productive hours in the workplace are the early
        afternoon hours.
2. None
        of the employees who work four days a week had volunteered to work that
        schedule, but all were assigned to it by their supervisors.
3. Working
        ten hours a day has allowed the most productive employees to work two
        hours alone each day in their respective offices relatively undisturbed by
        fellow employees.
4. Employees
        at SaleCo are compensated not on the basis of how many hours a week they
        work but on the basis of how productive they are during the hours they are
        at work.
5. Those
        SaleCo employees who have a four-day workweek do not take any of their
        office work to do at home on Fridays.