All of the following are protected characteristics of employees under federal EEO laws EXCEPT:

The choice regarding being under 40 years old is correct as it is not considered a protected characteristic under federal Equal Employment Opportunity (EEO) laws. Federal EEO laws protect individuals from discrimination based on certain categories, which include race, color, gender, sexual orientation, national origin, and religion.

However, age discrimination is specifically protected for individuals who are 40 years old or older under the Age Discrimination in Employment Act (ADEA). Therefore, being under 40 does not afford the same protections, as the ADEA is designed to prevent discrimination against older workers rather than those who are younger.

By understanding this distinction, it becomes clear why the characteristic of being under 40 years old does not fall under the protections designed by federal EEO laws.