The ancestor of C Language (CeeLanguage). As well as C, B was created by K&R [see ChickenAndEggProblem]
Brian Kernighan had no part in the creation of B or C. Ken Thompson created B, and Dennis Ritchie created C.
More specifically, Dennis Ritchie says (in http://www.cs.bell-labs.com/who/dmr/chist.html) that BeeLanguage is the parent of CeeLanguage.
Unlike C, B has really limited features. It has only one type: the cell (essentially a machine word). The first implementations used DirectThreadedCode instead of being compiled.
See also BcplLanguage which was its predecessor.
Incidentally, Dennis Ritchie's paper explains the origin of the default unix binary name a.out as being output from the assembler on the PDP-7 being used to develop the first Unix.