Which of the following techniques is used when a system performs the penetration testing with the objective of accessing unauthorized information residing inside a computer?

A biometrician is a person who applies statistical methods to biological facts and data, which is completely unrelated to penetration testing techniques.

Van Eck Phreaking is a form of electronic eavesdropping that captures electromagnetic emanations from computer monitors to reconstruct screen content, a specific type of information access but not a general penetration testing technique focused on accessing unauthorized 'information residing inside a computer' via network interaction.

Port scanning is a fundamental technique in penetration testing where a system or network is probed to discover open ports and services, which can reveal vulnerabilities or potential entry points for an attacker to gain unauthorized access and extract information. Identifying open ports is often a prerequisite for many types of attacks aimed at accessing internal data.

Phreaking generally refers to the act of circumventing telecommunications systems, primarily telephone networks, to make free calls or other unauthorized services, not directly about accessing data inside a computer via penetration testing.