Security testing that involves direct interaction with a target, such as sending packets to a target. Response:

Active security testing, also known as active scanning or probing, refers to the process of directly engaging with a target system or network by sending specifically crafted inputs, like network packets, to observe its behavior and identify vulnerabilities. This direct interaction helps reveal how a system responds to various stimuli, thereby uncovering potential weaknesses.

Recovery Point Objective (RPO) is a disaster recovery metric related to data loss, not a type of security testing.

Internal Security Testing describes the location of the testing (from within the organization's network), not the methodology of direct interaction.

A General Support System (GSS) is an information system that provides major application components or infrastructure for multiple applications, not a type of security testing.