What is the merchant category code required for petroleum merchants using pay-at-the-pump unattended terminals?

The correct answer identifies the merchant category code (MCC) specifically designated for petroleum merchants operating pay-at-the-pump unattended terminals. The MCC 5542 is assigned to "Service Stations (with or without Ancillary Services)," which encompasses self-service gas stations at which customers can pay at the pump without needing to visit an attendant.

This specific classification is crucial for transaction processing and reporting, which affects how payments are managed and the fees associated with credit card transactions at these locations. Understanding the correct MCC ensures compliance with industry standards and helps in the accurate allocation of transactions for accounting and fraud detection purposes. Thus, recognizing 5542 as the appropriate code for these types of merchants is essential for anyone involved in the payment processing industry.