关于GMAT逻辑的题 Industrial accidents are more common when some of

关于GMAT逻辑的题
Industrial accidents are more common when some of the people in safety-sensitive jobs have drinking problems than when none do.Since,even after treatment,people who have had drinking problems are somewhat more likely than other people to have drinking problems in the future,any employer trying to reduce the risk of accidents should bar anyone who has ever been treated for a drinking problem from holding a safety-sensitive job.
Which of the following,if true,most seriously undermines the argument above?
A.Some companies place employees who are being treated for drinking problems in residential programs and allow them several weeks of paid sick leave.
B.Many accidents in the workplace are the result of errors by employees who do not hold safety-sensitive jobs.
C.Workers who would permanently lose their jobs if they sought treatment for a drinking problem try instead to conceal their problem and continue working for as long as possible.
D.People who hold safety-sensitive jobs are subject to stresses that can exacerbate any personal problems they may have,including drinking problems.
E.Some industrial accidents are caused by equipment failure rather than by em
C选项是如何起得削弱作用呢?

（本人不是高手~）
文章是说：喝酒已经treatment的人,比一般人更容易引起事故.而且给出了建议：不要让这种人再从事这种工作~
b,d和e是扯淡的选项；
a支持了文章观点；
c：为了能够干这项活,瞒着不说比去treatment要好得多~ 文章的argument是说为了少点事故这个目的,提出了不让这些人干活的方法；但是假如这样做,人们就会隐瞒不报,这样就无法达到“少点事故”的目的,从而削弱了argument~
（表述能力不好,不知道您能不能看懂~）