The situation in which an employee knowingly allows someone access to a restricted area without verifying authentication is called Tailgating. Here's why: Piggybacking (Option A) refers to an unauthorized person following an authorized person into a secure area without their knowledge. Shoulder surfing (Option C) involves someone observing sensitive information (such as passwords) by looking over another person's shoulder. Phishing (Option D) is a form of social engineering where attackers deceive individuals into revealing confidential information. Therefore, the correct answer is B. Tailgating