Barter system- A method of exchange when no money is involved.
B and C can't be the answers because they are not exchanging anything.
D can't be the answer either because there is money involved.
So your answer is A) You trade an apple for a banana at school. because you are exchanging something with someone for something else thats not money.
Hope this Helps!!
I’m just gna take the free points here
No human brain can indicate that much how much we are not more than that
