Answer: A. Ledger
Explanation: The ledger is a book for keeping notes, especially one for keeping accounting records; It is the collection of accounting entries consisting of credits and debits thus representing the accounts for a business entity. All debits are recorded on the debit side of the ledger and all credits on the credit side according to dates. The ledger is also called the principal book of account, an indication of its relevance in running a business.
Entries in an accounting ledger might include cash accounts, accounts receivable, investments, inventory, accounts payable, accrued expenses, deposits etc.