Answer: From the given comprehension, 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, if true, provides the most reason to doubt that the president's plan, if implemented, will achieve its stated purpose.
Here, in this case the workers were productive since they were getting a two hour break, but what if they don't get this break. There are chances , they will not be as productive as before.