Which grape varieties must be listed in order of proportion if multiple varieties are on a label?

The correct answer indicates that grape varieties must be listed in order of their proportion when multiple varieties appear on a label. This practice is important because it provides transparency and accurate information to consumers about the composition of the wine they are purchasing. By requiring the varietal percentages to be listed in descending order of their proportions, it allows wine lovers to understand the main characteristics and influences that each grape variety contributes to the wine.

This requirement is particularly relevant in regulated wine regions and helps in maintaining consistency and quality within the winemaking industry. Knowing the proportions can guide consumers in their choices, especially those looking for specific flavor profiles or experiences that certain grape varieties are known for.

In other contexts, the other options do not fulfill this informative standard. Listing any variety arbitrarily or favoring the most expensive or first alphabetical varieties would not provide consumers with a clear understanding of the wine's makeup. Hence, the rule to specify varietals by proportion enhances the integrity and appeal of the wine industry while aiding consumers in making educated decisions.