CPL was a British project to create an all-singing all-dancing programming language.  The Common Programming Language was developed in the early 1960s.

And the Basic combined programming language(BCPL)  was a smaller language which was good for low-level programming. Well suited for writing compilers and system code for other languages.

B is a programming language developed at Bell Labs circa 1969. It was invented by Ken Thompson and Dennis Ritchie.
B was derived from BCPL, and its name may be a contraction of BCPL. Thompson’s coworker Dennis Ritchie speculated that the name might be based on Bon, an earlier, but unrelated, programming language that Thompson designed for use on Multics.

C is a general-purpose, imperative computer programming language, supporting structured programming, lexical variable scope and recursion, while a static type system prevents many unintended operations.

C was originally developed by Dennis Ritchie between 1969 and 1973 at Bell Labs, and used to re-implement the Unix operating system.

The name of C was chosen simply as the next after B.