Which of the following is NOT a protected category of Equal Opportunity (EO)?

The category of age is not a protected characteristic under certain Equal Opportunity (EO) laws when considering the context of specific employment discrimination laws, such as Title VII of the Civil Rights Act of 1964. This federal law protects individuals from employment discrimination based on race, color, religion, sex, or national origin. The other categories listed—sex, religion, and color of skin—are explicitly protected under these laws.

However, age is protected under a separate legislation known as the Age Discrimination in Employment Act (ADEA), which specifically protects individuals who are 40 years of age or older. This distinction is what makes age not universally classified among the main protected categories in general EO discussions as presented in this question. Understanding these classifications is crucial for grasping the scope and application of discrimination laws in the workplace.