Critical Reasoning

In the past, the majority of the most productive employees at
National Machine's corporate ofices have worked a trial schedule
of nine hours a day, four days a wek, and four hours on Friday. As
a result of this trend, and in an in an effort to further increase
productivity, the cheif executive of National Machine plans to
institute the same work hurs for all employees at the company's
corporate offices. After this plan is implemented, general
productivity among employees at the company corporate offices
should increase accordingly.

Which of the followings, if true, most weakens the above
argument?

A. Late afternoon hours are, generally, the least producrive hours
worked by employees at National Machine's corporate offices.
B. The employees who have worked the referenced schedule for
the past year voluntered to do so
C. National Machine's are paid based on productivity and hours worked,
rather than solely on hours worked
D. The National Machine corporate employes who have been working
the referebced shedule for the past year voluntred to do so and they
are among the most motivated employees in the company
E. The National Machine corporate employees who voluntered to work
the referenced schedule for the past year have generaly liked that
schedule better than the usual schedule followed by the remainder of
corporate employees.

IMO
D