A company is allowing a BYOD policy for its staff. Which of the following is a best practice that can decrease the risk of users jailbreaking mobile devices?

A. Install a corporately monitored mobile antivirus on the devices.

B. Prevent the installation of applications from a third-party application store.

C. Build a custom ROM that can prevent jailbreaking.

D. Require applications to be digitally signed.

Please explain your reasoning. Need to get this correct. I've seen people say it's D and others say A and even B.