Which processing method requires the cardholder to enter a personal identification number?

The processing method that requires the cardholder to enter a personal identification number is PIN-based Processing. This method is specifically designed for transactions that enhance security by verifying the identity of the cardholder through a unique PIN that they must input during the transaction. PIN-based Processing is commonly used for debit card transactions in retail environments or ATMs, where the cardholder's identity is confirmed which minimizes the risk of fraud.

In contrast, Online Billing typically involves transactions that might be completed without the need for such verification, focusing more on convenience rather than the immediate identity confirmation through a PIN. Signature-based Processing allows transactions to be verified by a signature rather than a PIN, relying on the merchant's ability to compare the signature on the receipt with the one on the back of the card. Offline Debit Processing may not necessitate immediate input of the PIN as the transaction can be authorized later, making it different from the PIN-based method, which requires real-time entry of the PIN for immediate authentication. Thus, the requirement for a cardholder to enter a PIN distinctly defines PIN-based Processing as the correct answer.