As a Condition of Being Allowed to Apply for a Job

As a condition of being allowed to apply for a job with Good Hands Industries,Charles is asked to waive his right to object to workplace searches.After signing the waiver,he is offered a job,and he accepts it.Sometime later,he is subjected to a search.If Charles seeks legal redress on the grounds that the search violated his privacy rights,his employer:

A) will be unable to successfully assert the waiver as a defense because it was not given voluntarily.
B) will be unable to successfully assert the waiver as a defense because Charles did not grant it intentionally.
C) will be unable to successfully assert the waiver as a defense because it was given by Charles prior to his job offer.
D) will be able to successfully assert the waiver as a defense because it was given in exchange for valuable consideration.