Final answer:
The appropriate response using the pronoun 'en' would be 'Oui, j'en ai'. 'En' is used to replace a partitive article followed by a noun, avoiding repetition.
Step-by-step explanation:
When answering the question 'Tu as du pain?', the appropriate response using the pronoun 'en' would be 'Oui, j'en ai'.
'En' is used to replace a partitive article followed by a noun, in this case 'du pain' which means 'some bread'. By using 'en', we avoid repeating the noun and instead refer back to it indirectly.
Here's an example: 'Tu as mangé tous les biscuits?' (Did you eat all the cookies?). 'Oui, j'en ai mangé quelques-uns' (Yes, I ate some of them).
Learn more about Using the pronoun 'en' in French