A BFOQ Defense Against a Claim of Age Discrimination, Based

A BFOQ defense against a claim of age discrimination, based on the fact that some people over a certain age have a trait which cannot be ascertained except by reference to age, can be established by

A) requiring all employees or applicants over the certain age to take a medical examination.
B) requiring all employees over a certain age to take a psychological examination.
C) requiring all employees over a certain age to go to vocational rehabilitation.
D) None of the choices are correct.