Which three types of files can be automatically placed in the flash recovery area (fast recovery area in 11g Release 2)?

B C and D are correct:

https://docs.oracle.com/cd/B19306_01/backup.102/b14192/setup005.htm

3.5.2 Files That Can Be Stored in the Flash Recovery Area
The files in the flash recovery area can be classified as permanent or transient. The only permanent files (assuming these are configured to be stored in the flash recovery area) are multiplexed copies of the current control file and online redo logs. These cannot be deleted without causing the instance to fail. All other files are transient, because Oracle will generally eventually delete these files, at some point after they become obsolete under the retention policy or have been backed up to tape. Transient files include archived redo logs, datafile copies, control file copies, control file autobackups, and backup pieces.