Your network contains one Exchange Server 2010 SP1 Client Access server named Server1.

You have a user named User1.

You need to limit the size of the attachments that User1 can download by using Windows Mobile 6.5 devices.

What should you do first?

A.
Create a new Exchange ActiveSync device access rule

B.
Create a new managed content settings

C.
modify the message size restriction for user1

D.
create new Exchange ActiveSync mailbox policy

Explanation:
(Exhibit)