Correct Answer:
Explanation/Reference:
Explanation:
A mail contact is a mail-enabled Active Directory contact that contains information about people or organizations that exist outside the Exchange organization. Each mail contact has an external email address. All messages sent to the mail contact are routed to this external email address.
A mail user is a mail-enabled Active Directory user that represents a user outside the Exchange organization. Each mail user has an external email address. All messages sent to the mail user are routed to this external email address. A mail user is similar to a mail contact, except that a mail user has Active Directory logon credentials and can access resources (can log in to the Office 365 portal).
A shared mailbox is a mailbox that is not primarily associated with a single user and is generally configured to allow access for multiple users.
A distribution group or distribution list is a mail-enabled Active Directory distribution group object that can be used only to distribute messages to a group of recipients.
References:
https://technet.microsoft.com/en-us/library/bb201680(v=exchg.150).aspx