What accounts do we use when "paid creditor on account"?

"Paid" always means cash - it's what you pay with.

"On account" means either accounts receivable or accounts payable. They aren't telling you so you have to determine it by context.

Remember that accounts receivables represents what a customer owes to you, and accounts payable represents what you owe to someone else. If you're the one doing the paying, which do you think it is?