The runtimes most associated with sandboxed isolation are gVisor’s runsc and Kata Containers, making C correct. Standard container runtimes (like containerd with runc) rely primarily on Linux namespaces and cgroups for isolation. That isolation is strong for many use cases, but it shares the host kernel, which can be a concern for multi-tenant or high-risk workloads.

gVisor (runsc) provides a user-space kernel-like layer that intercepts and mediates system calls, reducing the container’s direct interaction with the host kernel. Kata Containers takes a different approach: it runs containers inside lightweight virtual machines, providing hardware-virtualization boundaries (or VM-like isolation) while still integrating into container workflows. Both are used to increase isolation compared to traditional containers, and both can be integrated with Kubernetes through compatible CRI/runtime configurations.

The other options are incorrect for the question’s intent. “rune, cgroups” is not a meaningful pairing here (cgroups is a Linux resource mechanism, not a runtime). “docker, containerd” are commonly used container platforms/runtimes but are not specifically the “sandboxed isolation” category (containerd typically uses runc for standard isolation). “crun, cri-o” represents a low-level OCI runtime (crun) and a CRI implementation (CRI-O), again not specifically a sandboxed-isolation grouping.

So, when the question asks for the group that provides additional sandboxing and elevated security, the correct, well-established answer is runsc + Kata.