Which Stipulation Is the Main Feature of the Americans with Disabilities

Which stipulation is the main feature of the Americans with Disabilities Act?

A) The act prohibits discrimination against people with a physical or mental disability who could perform a job with reasonable accommodation.
B) The act requires that men and women receive equal pay for equal work.
C) The act makes it illegal to "discriminate against any individual with respect to his compensation, terms, conditions, or privileges of employment, because of such individual's race, color, religion, sex, or national origin."
D) The act protects workers over age 40 from discrimination.