$437.$ Sensitive data was leaked from a user's smartphone. A technician discovered an unapproved application was installed, and the user has full access to the device's command shell. Which of the following is the NEXT step the technician should take to find the cause of the leaked data?

A$.$ Restore the device to factory settings.

B$.$ Uninstall the unapproved application.

C$.$ Disable the ability to install applications from unknown sources.

D$.$ Ensure the device is connected to the corporate WiFi network.