Source document used for cash sale is:

The correct answer is a) cash memo.

Explanation:

A source document is a paper or electronic record that provides evidence of a transaction. It is used to initiate the recording of a transaction in the accounting system. In the case of a cash sale, the source document used is a cash memo.

Cash Memo:

A cash memo is a document that is prepared at the time of a cash sale. It serves as proof of the transaction between the seller and the buyer. The cash memo includes important details such as the date of the transaction, the name and address of the seller and buyer, a description of the goods or services sold, the quantity, the unit price, and the total amount due. It also includes the mode of payment, which in this case is cash.

Other Options:

- Invoice and Bill: While invoices and bills are commonly used in sales transactions, they are not specifically used for cash sales. Invoices and bills are typically used when goods or services are sold on credit or when payment is due at a later date.

- Cash Receipt: A cash receipt is a document that is prepared when a payment is received, regardless of whether it is a cash sale or a sale on credit. It serves as proof of payment and includes details such as the date, the name of the payer, the amount received, and the purpose of the payment.

- Debit Note: A debit note is a document that is prepared to request a payment from a customer for goods or services that were undercharged or not charged at all. It is not used for cash sales, but rather for rectifying errors or omissions in previous invoices or bills.

Conclusion:

In summary, the source document used for a cash sale is a cash memo. It provides evidence of the transaction and includes important details such as the date, seller and buyer information, description of goods or services, and the total amount due.