san_policy.xml

<?xml version='1.0' encoding='utf-8' standalone='yes'?>
<unattend xmlns="urn:schemas-microsoft-com:unattend">
  <settings pass="offlineServicing">
    <component
        xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        language="neutral"
        name="Microsoft-Windows-PartitionManager"
        processorArchitecture="x86"
        publicKeyToken="31bf3856ad364e35"
        versionScope="nonSxS"
        >
      <SanPolicy>4</SanPolicy>
    </component>
    <component
        xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        language="neutral"
        name="Microsoft-Windows-PartitionManager"
        processorArchitecture="amd64"
        publicKeyToken="31bf3856ad364e35"
        versionScope="nonSxS"
        >
      <SanPolicy>4</SanPolicy>
    </component>
  </settings>
</unattend>