Final answer:
The Immigration and Nationality Act prohibits discrimination based on citizenship, immigration status, or national origin during the I-9 process, and the EEOC enforces federal anti-discrimination laws.
Step-by-step explanation:
The law that prohibits discrimination against individuals based on their citizenship or immigration status, or their national origin in the Form I-9, Employment Eligibility Verification Process, is the Immigration and Nationality Act. This act protects the rights of legal immigrants and requires employers to ask for proof of citizenship while protecting legal immigrants from discrimination during the hiring process. Additionally, in the United States, federal anti-discrimination laws are administered by the U.S. Equal Employment Opportunity Commission (EEOC), which enforces Title VII of the Civil Rights Act of 1964, prohibiting employment discrimination on various bases including national origin.