The word that completes the sentence and means "relating to race, nationality or culture" is:
A. ethnic
Explanation:
1. In the sentence provided, the context is about different types of food preferences like Mexican and Indian, which are related to specific cultures or nationalities.
2. The word "ethnic" is used to describe characteristics or customs specific to a particular cultural group, race, or nationality.
3. Therefore, in this context, the word "ethnic" is the most appropriate choice as it aligns with the idea of food preferences associated with specific cultural backgrounds.