An attacker follows an employee through a badge-secured door before the door closes. Which of the following types of attacks is occurring?

Shoulder surfing involves directly observing someone's screen or keyboard to steal information, which is different from gaining physical access by following someone.

Tailgating, also known as piggybacking, is a physical security breach where an unauthorized person gains entry to a restricted area by closely following an authorized individual who has legitimately opened a secure access point, like a badge-secured door.

Phishing is a social engineering attack conducted via electronic communication (e.g., email) to trick individuals into revealing sensitive information, not a method of physical entry.

On-path, or Man-in-the-Middle, is a type of cyberattack where an attacker intercepts and potentially alters communication between two parties, not a physical access method.