Explanation/Reference:
In Exchange 2016, you can create mobile device mailbox policies to apply a common set of policies or security settings to a collection of users. After you deploy Exchange ActiveSync in your Exchange 2016 organization, you can create new mobile device mailbox policies or modify existing policies.
Use the Set-MobileDeviceMailboxPolicy cmdlet to modify mobile device mailbox policies.
Incorrect Answers:
D: Use the Set-ActiveSyncOrganizationSettings cmdlet to set the MicrosoftExchange ActiveSync settings for the organization.
References: https://technet.microsoft.com/en-us/library/bb123783(v=exchg.160).aspx