Your company is planning to migrate to Microsoft Exchange Online. The company employs 1,000 people, each with a mailbox currently located on Exchange 2010 on-premises. You estimate that it will take a minimum of four weeks to migrate all mailboxes from on-premises Exchange to Exchange Online.
The company has the following migration requirements:
During the migration, do not change the existing Microsoft Outlook profiles and .ost files used by the

employees.
Ensure that email messages sent between on-premises mailboxes and online mailboxes during the

migration are secure.
Do not send email messages between on-premises mailboxes and online mailboxes over the Internet in

plain text.
You need to select the migration strategy that meets the requirements.
Which migration strategy should you use?
Correct Answer: A
Explanation/Reference:
Explanation:
You can use a hybrid migration to migration from Exchange 2010 to Exchange Online.
Note: In the Deployment Assistant, a hybrid deployment is when you create a new Exchange Online Exchange organization in Microsoft Office 365 for enterprises and then connect it to your existing on- premises Exchange 2010 organization by configuring Active Directory synchronization and using the Hybrid Configuration wizards.
Incorrect Answers:
B: IMAP migration is targeted at customers who may be using non-Exchange-based mail systems in their current hosted environment or have access to the data only by using the IMAP 4 protocol.
C, D: You can't use a staged migration to migrate Exchange 2013 or Exchange 2010 mailboxes to Office
365.
References: https://support.office.com/en-us/article/Decide-on-a-migration-path-0d4f2396-9cef-43b8-9bd6-
306d01df1e27?ui=en-US&rs=en-US&ad=US