Final answer:
The question 'Are you legally blind?' is potentially discriminatory under federal law as it relates directly to a disability, which is protected by the Americans with Disabilities Act.
Step-by-step explanation:
When reviewing the list of interview questions for potential discriminatory content under federal law, it is essential to identify any question that could relate to an applicant's personal characteristics protected by anti-discrimination legislation. The question that stands out as potentially discriminatory is "Are you legally blind?", as the Americans with Disabilities Act (ADA) prohibits job discrimination against qualified individuals with disabilities. This question directly inquires about a disability, which could be used to discriminate against an applicant. Employers should focus instead on asking whether the applicant can perform the essential functions of the job with or without reasonable accommodation, as phrased in option C, which is related to the job's physical requirements and not to the individual's disability status.