What is the BEST example of shoulder surfing?

Shoulder surfing is a technique where an individual observes someone else in order to obtain confidential or sensitive information unknowingly. The best example of shoulder surfing is watching a customer enter a PIN at an ATM. In this scenario, the observer is directly gaining access to a personal identification number, which is a critical piece of information that can lead to unauthorized access to the customer's bank account.

This form of covert observation is facilitated by the proximity of the observer to the ATM user and typically occurs in a public setting, making it easier for the observer to gather this information without raising suspicion. The essence of shoulder surfing lies in the act of visually eavesdropping on another person’s private actions to steal sensitive data.

The other choices involve different methods of gaining unauthorized access or information, but they do not exemplify the concept of shoulder surfing. For example, gaining access by following someone into a restricted area relies on physical security breaches, while leaving a flash drive with malware represents a form of social engineering or sabotage. Convincing an authorized user to share login information relies more on manipulation or deception rather than direct observation of someone's actions, which is the hallmark of shoulder surfing.