Through which service can debit keys for the PIN pads be requested?

The option referring to VeriShield Remote Key is correct because it is specifically designed for securely managing encryption keys for payment devices, including PIN pads. This service enables the secure transmission and management of cryptographic keys, which is essential for maintaining the security of debit transactions. By using VeriShield Remote Key, merchants can simplify the process of key management, ensuring that the PIN pads are always equipped with the latest keys and security standards, thus reducing the risks associated with key exposure or mishandling.

In contrast, the other services listed do not specifically address the key management needs for PIN pads. For example, Verifone Remote Software Delivery focuses on software updates rather than key management, while Configuration Client is primarily used for configuring device settings rather than handling encryption keys. Therefore, VeriShield Remote Key is the only choice that directly relates to the request and management of debit keys for PIN pads, making it the appropriate answer.