The correct answer is C.
OBJ-2.3: The most serious vulnerability discovered is one that could allow remote code execution to occur. Since this buffer overflow vulnerability is known to allow remote code execution, it must be mitigated first to prevent a security breach most effectively. While the other issues should be addressed eventually, you need to prioritize the most critical one (remote code execution) on a public-facing IP address. A public-facing IP address means the device is accessible from the internet.