Which of the following is an example of an A2A transaction?

An A2A (Account to Account) transaction refers to transfers of funds that occur between two bank accounts, typically without the intermediary involvement of an account holder's debit or credit card at the point of sale. In the context provided, a wire transfer payment using Fedwire is a quintessential example of an A2A transaction, as it directly facilitates the transfer of funds from one bank account to another electronic account.

This type of transaction is usually executed to ensure immediate and secure transfer of funds, highlighting the efficiency and direct nature of bank account interactions. In contrast, the other scenarios mentioned involve the use of payment methods that are not primarily about transferring directly from one account to another, such as using a debit card or credit card, both of which involve an intermediary process in the transactional flow. Similarly, paying a bill via mobile app may also initiate a method of payment that does not solely rely on a direct A2A transfer. Thus, Fedwire is the correct representation of an A2A transaction due to its direct account-to-account nature.