Data and resource forks and those .filename files

This is really dwelling on the details. Considering forks, it seems there are
several possibilities for a file, and my questions is Which of the following,
if any, is NOT a valid construct for a Macintosh file? Some will seem
obviously correct, but I had to include them for completeness. In these
examples, note that I make the distinction between an empty fork and no fork
at all:

A) Data in both forks.
B) A data fork with data and an empty resource fork.
B) A resource fork with data and an empty data fork.
D) A data fork and no resource fork.
E) A resource fork and no data fork.
F) Data, but no forks whatsoever.

Thanks.

 

All possible, though I'm not 100% sure of E. There is a definite
difference between an empty resource fork and no resource fork. (An
empty resource fork contains structural data.) There is no such
difference with data forks, so thus it may be that any file is
considered to have a data fork.

Not possible, because that's meaningless, at least as far as the file
system is concerned. If you have a file, it *must* have either a data
or resource fork.

 

F is not possible. Every Mac file has one or both forks. In other
words, a flat file containing data has a data fork.

 

F is not real.
B and B are possible, but exceedingly unlikely. A, D and E were all
quite common prior to OS X. Under OS X, the resource fork isn't actually
deprecated, but its use is discouraged in new development.