"Thank you for your piece of advice."
Translation:Merci pour ton conseil.
I was thrown by the English expression- we usually just say "thank you for your advice". Had this been the prompt I would have responded with the correct answer. While one can understand "piece of advice", it's not usual. I translated this literally because it was so odd.
Problem is that advice is an uncountable noun in English while it is in French, and the purpose of this practice was to demonstrate this difference. Unfortunately, the choice of sentence is poor.