Your company has a Microsoft Exchange Server 2007 environment. Employees have Windows Mobile 6.5 devices. You configure your Exchange Server environment for SSL communication that uses a third-party certificate authority (CA). You need to provide employees with a certificate file that they can install directly on their Windows Mobile devices by using File Explorer. Which type of certificate should you create?

A.
Install a root certificate that has a .cer extension.

B.
Install a root certificate that has a .der extension.

C.
Install a personal certificate that has a .p7b extension.

D.
Install a personal certificate that has a .pem extension.