A. An Intel-based Mac will not start up without the GUID partition map.

B. You should not use GUID. Apple Partition Map (APM) is the default partition map for Intel-based Macs.

C. The GUID partition scheme contains the necessary standard apps for OS X.

D. Master Boot Record (MBR) requires a GUID partition map.

E. Firmware updates for Intel-based Macs require a GUID partition scheme.

F. Any of the partition schemes provided by Disk Utility will work.