Final answer:
The most secure way to deploy a legacy application is by sandboxing, which isolates the application from the host system, reducing security risks.
While placing it on an encrypted drive secures the data at rest, stress testing and dynamic testing do not offer direct protection during operation.
Therefore, the correct answer is: option C. Sandboxing
Step-by-step explanation:
Sandboxing is a cyber security practice where you run code, observe and analyze and code in a safe, isolated environment on a network that mimics end-user operating environments.
Sandboxing involves running the application in a controlled and isolated environment, which prevents it from affecting the host system and other applications.
This method dramatically reduces the security risks associated with running legacy software, which often contains vulnerabilities no longer patched by the original developers.
In contrast, while placing an application on an encrypted drive protects the data at rest, it does not mitigate the risks when the application is running.
Stress testing and dynamic testing are methods used to evaluate the performance and security of an application; however, they do not inherently protect against the exploitation of the application.