While specialized books exist for purchases and sales returns, if a specific 'Purchases Return Journal' is not maintained, such transactions are recorded in the General Journal (also known as the Journal Proper). The provided answer 'C' is correct in the context of general accounting practice where specific subsidiary books might be limited.

The General Journal, often referred to as the book of original entry, is used to record all financial transactions in chronological order as they occur, before they are posted to the respective ledger accounts.

When a cheque is received and deposited into the bank on the same day, the transaction directly increases the bank balance. Therefore, it is recorded in the bank column of the cash book as a debit entry, reflecting the increase in the bank asset.

A two-column cash book is designed to record both cash transactions and discount transactions (both discount allowed and discount received). This format is efficient for businesses that frequently offer or receive cash discounts, as it allows for the systematic recording of these adjustments alongside the primary cash movements in a single ledger.

A contra entry occurs when a transaction affects both the cash and bank columns simultaneously, such as depositing cash into the bank or withdrawing cash for office use. This requires columns for both cash and bank, found in two-column and three-column cash books.

The discount column on the debit side of a cash book represents discounts allowed to customers. Since discounts allowed are an expense to the business, they follow the nominal account rule of debiting all expenses and losses. Therefore, the total of this column is posted to the debit side of the Discount Allowed account in the ledger.

A double column cash book typically contains two columns on each side, usually representing cash and bank transactions. While some versions include a discount column (making it a triple column cash book), the standard double column format is specifically designed to track both cash and bank movements.

A two-column cash book is a variation of the cash book that includes two amount columns on both the debit and credit sides. Typically, these columns are used to record cash and discount transactions. This design helps in tracking the cash balance while simultaneously recording any discounts allowed to customers or received from suppliers, simplifying the accounting process.

Since the discount received reduces the amount payable to the supplier, it represents a reduction in cash outflow. To correct the error where the full gross amount was recorded, the discount must be credited to the cash book to reflect the actual lower payment made.

A contra entry occurs when a transaction affects both the cash account and the bank account simultaneously. For example, when cash is deposited into the bank or cash is withdrawn from the bank for office use, the entry must appear on both sides of the double-column cash book. This ensures that the internal movement of funds between cash and bank is captured without affecting the total cash position.