Which of the following is a prohibited discrimination ground in EU law?

The correct choice identifies the grounds of discrimination that are explicitly prohibited under EU law. The European Union has established several legal frameworks, such as the Equality Directive and various anti-discrimination regulations, which specifically mention sex, race, age, religion, disability, and sexual orientation as grounds for protection against discrimination in employment and occupation.

These protected characteristics are critical as they reflect the EU's commitment to ensuring equality and reducing discrimination across member states. By recognizing these categories, the EU promotes a diverse and inclusive workforce and seeks to prevent unfair treatment in various spheres of life, including employment, education, and access to services.

The other options do not represent grounds recognized under EU anti-discrimination law. Marital status may be covered under different legislation in some member states but is not a universally recognized ground in EU law. Employment history and political affiliation, while relevant to certain contexts, do not fall under the protected categories specified in EU legislation focusing on discrimination.