Multi-select problem: How does the next paragraph end?

How to prove age discrimination in hiring
Read up on federal law.
Federal law prohibits discrimination in hiring on the basis of age when the applicant is 40 or older. The primary motive for refusing to hire someone must have been age.

Choose your answer from: a. Federal law prohibits employment discrimination as a result of age. Should you be a prospective employer, you would have no reason to discriminate on the basis of age.; b. Younger people have a higher chance of not being fired if they have the age-of-consent requirement for employment. Be aware that certain age-related statutes prohibit discrimination when working 10 hours a week, or working 50 hours a week.; c. In a relatively traditional scenario, the applicant may have gotten a disability in order to get hired. This means that much of the law on age discrimination must be proven.; d. In other words, there cannot be other legitimate reasons mixed in for refusing to hire someone (such as not wanting to pay a higher salary for a more experienced applicant). Federal law does not apply to all employers.;
d.