Final answer:
The appropriate form of the partitive to fill in the blank is 'des'
Step-by-step explanation:
In the given sentence, the appropriate form of the partitive to fill in the blank would be des.
The word 'des' is used as the partitive article before plural countable nouns. In this case, 'légumes' is plural, so we use 'des', which means 'some' in English.
For example, if we want to say 'They eat some vegetables', we would say 'Elles mangent des légumes'.
Learn more about Use of partitive article in French