An organization implemented a BYOD policy for employees to use their mobile devices for work$-$related tasks. The organization's IT department identified concerns about the security risks associated with BYOD. They determined that employees' mobile devices must meet the security requirements to protect sensitive company data. Considering the scenario, which of the following measures is the MOST effective way to enhance the security of employees' mobile devices under the BYOD policy?

A$.$Restricting all access to company resources from mobile devices

B$.$Providing employees with company$-$owned mobile devices

C$.$Using MDM solutions to centrally control employees' mobile devices

D$.$Enforcing complex passwords for all employee mobile devices