I used the instructions to establish a link to an external drive
in mklink error: Cannot create a file when that file already exists,
but now have both the C: and the external drive D: with a backup when I only wanted the D: version. I had deleted the backup in C: before starting the backup.
I also confirm that the only instruction that worked was:
mklink /J "%APPDATA%\Apple Computer\MobileSync\Backup" "D:\iPhoneBackup"
where iPhoneBackup is the folder I established in D:.
I appreciate your input.