Which of the following is NOT a European minority ethnic group?

The correct answer fro your question is option (Walloons).

Explanation:

Norwegians are commonly a North German Ethnic Group but has Norway as their native. Now the decedents from this ethnic group can be found widely in Canada, United Kingdom, United States, Brazil, Australia, Argentina and more.

Basques are indigenous ethnic group of people who lived in North-central Spain and Western France.

Wallons are ethnic people native to Belgium

Saami are finno-Ugric people who lived in Norther Europe.