Concept:A cash book is a special record that acts as both a subsidiary book for recording transactions and a ledger account for cash and bank balances.
Explanation:A subsidiary book is used to record transactions in chronological order before they are transferred to the main ledger.
A ledger is the principal book that contains classified accounts and summaries for the trial balance.
The cash book records all cash receipts and payments, as well as bank deposits and withdrawals, on a daily basis.
Because it provides the first written record of cash and bank transactions, it serves as a subsidiary book.
At the same time, the cash book contains the cash account and the bank account, which are ledger accounts.
Therefore, cash and bank balances are taken directly from the cash book when preparing the trial balance.
The purchases day book and returns outward book are only subsidiary books, so their totals must still be posted to the ledger.
The general journal is also a subsidiary book used mainly for corrections, transfers, and opening entries, not for maintaining account balances.
Only the cash book combines the role of a subsidiary book with that of a ledger.
Answer:D. cash book