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?