gwd-11-8请教一道费解的逻辑

Q8:

Personnel officer:  The exorbitant cost of our health-insurance benefits reflects the high dollar amount of medical expenses incurred by our employees.  Employees who are out of shape, as a group, have higher doctor bills and longer hospital stays than do their colleagues who are fit.  Therefore, since we must reduce our health-insurance costs, we should offer a rigorous fitness program of jogging and weight lifting to all employees, and require employees who are out of shape to participate.

The conclusion reached by the personnel officer depends on which of the following assumptions?

1. A person who is fit would receive a routine physical checkup by a doctor less regularly than would a person who is out of shape.
2. The medical expenses incurred by employees who are required to participate in the fitness program would be less than those incurred by employees who are not required to participate.
3. The strenuous activities required of out-of-shape employees by the program would not by themselves generate medical expenses greater than any reduction achieved by the program.
4. The fitness program would serve more employees who are out of shape than it would employees who are fit.
5. The employees who participate in the fitness program would be away from work because of illness less than would the employees who do not participate.

   Answer: c

为什么b不正确呢？ 它取非后=参加program的员工比不参加program的员工医疗费高--〉可以weaken原文的推理。请NN帮忙看看

注意看原文，program只是计划降低参加的人的expense，而不一定要降到比没参加的人还低。