Which of the following is a common, passive reconnaissance technique employed by penetration testers in the early phases of an engagement?

Open-source intelligence (OSINT) is a passive reconnaissance technique that involves collecting information about a target from publicly available sources, such as social media, company websites, news articles, and public databases. This is done in the early phases of an engagement to gather as much information as possible without directly interacting with the target's systems, thus minimizing the risk of detection. Port scanning is an active reconnaissance technique that involves sending packets to a target's ports to determine which services are running. Pivoting is a post-exploitation technique where an attacker uses a compromised system to gain access to other systems within the network. Exploit validation is a step taken after an exploit has been attempted to confirm its success.