Security patches address known vulnerabilities and should be applied promptly to mitigate potential risks. While all the options provided are components of a good security posture, applying security patches is generally the most effective single action to protect against known security issues. Regular updates and patch management are critical components of maintaining OS security. Long-term support (LTS) versions of OS provide stability, and scheduled updates ensure regular enhancements, but they might not address immediate security threats as effectively as targeted security patches. Moreover, although hot fixes can address specific issues, they are not always focused solely on security and may not cover all known vulnerabilities.