The question was which transaction changes will be contain in the full backup?

In my understanding all transaction changes until the point where backup finish are recorded in the backup file. Since transaction 4 committed after backup was finish therefore only the changes up to the point of backup finished from transaction 4 will be recorded.

Another story is when backup is used to restore database from backup file then ALL changes for transaction 4 contained in backup file will be rollback since transaction 4 did not have commit statement as other three transaction have.

Regards

Krystian