Answer:
D. At-will employment
Step-by-step explanation:
Don't be fooled! At-will employment actually refers to two things:
at-will termination, meaning an employer can fire you for any reason (other than illegal)
and at-will quitting, meaning the employee can quit at any time, for any reason.
An example of this would be a boss firing an employee for wearing a gray shirt to work, which is the boss's least favorite color. It's messed up, but under at-will employment, it can be done. Moments later, another employee leaves without warning or notice, and under the same rule, it can be done.
In contrast with the other options, D has nothing to do with diversity.