Okay, without the "-r" option, example 3 now works as desired. The name of the source directory from the top level is inside the archive. However, I cannot explain why in example 3 (with "-r") the entire drive was searched, but in example 1 (also with "-r") it wasn't. But never mind. Thank you for your prompt reply.
7z.exe: catastrophic archiving entire drive or missing name of source directory inside archive file