Arguments over whether it should be called "D" or "P".
Before "B" there was "BCPL" https://en.wikipedia.org/wiki/BCPL
The original "Hello, world!" program was written in BCPL. BCPL influenced B, which in turn influenced C.
I heard there was an “A” language - the only thing left of it was a.out in UNIX, and a.exe in gcc.