Which of the following is a type of testing that analyzes application source code for vulnerabilities?

Static Application Security Testing (SAST) is the correct answer because it involves the analysis of application source code to identify vulnerabilities before the code is run. This form of testing is crucial for developers as it allows them to detect and fix security issues early in the development lifecycle, which can reduce the costs associated with remediating vulnerabilities after deployment.

SAST tools examine the code structure, which can include identifying insecure coding practices, data leaks, and other potential vulnerabilities by analyzing the code itself, rather than its run-time behavior. This proactive approach not only strengthens security but also educates developers on best practices in writing secure code.

In contrast, other testing types mentioned focus on different aspects. For instance, RASP is employed during runtime to protect applications by monitoring their behavior while they execute but does not analyze the source code directly. Dynamically Analyzed Security Testing focuses on testing the applications in a running environment to uncover vulnerabilities, while penetration testing simulates an attack on a running application to exploit its weaknesses, rather than studying the source code for vulnerabilities.