Which feature of Exchange is required to allow Outlook to fully synchronize content (mail folders, contacts, calendars, and tasks)?

Which feature of Exchange is required to allow Outlook to fully synchronize content (mail folders, contacts, calendars, and tasks)?

• MAPI
• IMAP
• ActiveSync
• POP3 

EXPLANATION

Exchange ActiveSync (commonly known as EAS) is a proprietary protocol designed for the synchronization of email, contacts, calendar, tasks, and notes from a messaging server to a smartphone or other mobile devices. The protocol also provides mobile device management and policy controls. The protocol is based on XML. The mobile device communicates over HTTP or HTTPS.