Final answer:
The highest quality Champagnes are labeled with 'Grand crus.'
Step-by-step explanation:
The correct answer is d. Grand crus.
The Champagnes that are rated as the highest quality by the CIVC (Comité Interprofessionnel du Vin de Champagne) have the privilege of putting 'Grand crus' on their label.
Grand crus are the highest classification of vineyards in the Champagne region of France. These vineyards are considered to produce the best quality grapes, resulting in the highest quality Champagnes.