Final answer:
The appropriate pair of words to fill in the blanks is 'du/en'.
Step-by-step explanation:
In the given dialogue, the appropriate pair of words to fill in the blanks is du/en. The correct response would be:
Est-ce qu'ils ont du chocolat?
Oui, ils en ont!
The word du is used to express the quantity or some of a masculine noun, like chocolat. The word en is used as a pronoun to replace a noun that has already been mentioned or understood, in this case, chocolat.
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