Which of the following refers to illegal access or use of funds?

The term "fraudulent use" specifically refers to the illegal access, misuse, or manipulation of funds or financial resources. It involves acts where someone uses another person's funds or financial information without their permission, typically for personal gain. This kind of behavior is often associated with crimes such as identity theft, credit card fraud, or account takeover.

In contrast, the other options do not directly pertain to the illegal access or use of funds. A "bank account decline" and "transaction decline" refer to situations where a bank or financial institution denies a transaction for reasons such as insufficient funds or account status. "Purse theft" involves the physical act of stealing a personal item and does not necessarily involve the illegal access or use of funds in the same context as fraudulent use does. Therefore, the most accurate option that encompasses illegal access to funds is "fraudulent use."