A restricted operating system intended for testing code is called what?

• A. VirtualBox
• B. Emulator
• C. Sandbox
• D. KVM

Answer: (C)

A sandbox is an isolated, restricted environment designed for safely running and testing code. In a sandbox, the program’s access to the host system is limited—files, network access, processes, and system calls are controlled or sandboxed so the code can’t affect the real system. This lets you observe behavior and catch bugs or malicious actions while keeping the host safe, and you can often reset or revert the environment between runs.

Why the other options don’t fit as well: virtualization technologies like VirtualBox or KVM create full virtual machines with separate guest operating systems, which is heavier and not inherently a restricted testing space. An emulator focuses on mimicking hardware or another platform to run software, not on providing a guarded execution space for testing untrusted code.