PGBench on Windows - connections are subprocesses?

Dear Members!

I have a question about PGBench for Windows (9,6).

I want to understand the working method of this tool for use well
in the test series.

This has more options, like connections (c).

As I tried the c controls how much concurrent connections must be used in
the test. For example c 10 increases with ten. It's ok.

But the number of threads option (j I think) confused me. At first I
thought the total connection number is simply the multiplication of c and j
(subconnections).
As I saw this is untrue.

So I don't know how this utility works really in the background.

a.)
It makes C subprocesses with connections and every of them makes his work
concurrently?

b.)
It makes N connections on one thread/process. Hut only one works at the
same time. J controls how much works at the same time. The other
connections are sleeping.
1. c started/has finished.
2. c started/has finished.
N. c started/has finished.
End.
(This is a little bit senseless)

c.)
It makes C subthreads and every thread has it's connection. They work
concurrently (like in case a).
It could be ok, but why can I set threads with the "j" option - when
subthreads must be equal with the number of connections.

Do you know something about the background of this utility?

We have to move to the next server which is different from the actual one,
and I need to measure them to detect the possible problems.
To compare the result I must understand the operations.

Very-very thank you for each answer you write!

Best regards
DD