Final answer:
Patch management is the process of distributing and applying software updates, including security patches, to ensure devices meet the company's security standards. It is the correct approach to address outdated endpoint security software on users' mobile devices to comply with the company's security policy.
Step-by-step explanation:
To address the issue of users' mobile devices running outdated versions of endpoint security software, the correct action to take would be C. Patch management. Patch management is the process of distributing and applying updates to software. These updates, or patches, often include fixes for security vulnerabilities that have been discovered since the release of the original version of the software. By implementing a robust patch management program, the company can ensure that all users' mobile devices are updated to meet the company's security standards and allow safe access to the network.
In contrast, vulnerability assessment and risk assessment are processes used to identify and evaluate security risks, but they do not involve the actual application of software updates. Device quarantine would prevent access to the network for non-compliant devices, which could be temporarily necessary until patches are applied, but it does not resolve the underlying issue. Incident management refers to the actions taken after a security breach has occurred and is also not directly related to updating software on devices.