Language B, written in by Ken Thompson in 1970, was developed as the language in which to write the code for the Unix operating system on a DEC PDP-7 (minicomputer of the time).
B was a typeless language. All data was just bits and any operators could be used on any data.
C evolved from B, but provides a variety of data types: characters, integers and floating point numbers of a variety of sizes plus a hierarchy of types created with pointers, arrays, and structures. In C each data type has an associated set of operators that can be performed on the type. Other operations are not allowed. The orignal language manual for C was published around 1978.
Both B and C were devloped at Bell Labs.
C++ was developed initially and primarily by Bjarne Stroustroup and also developed at Bell Labs. A course on C++ was held by Stroustroup at Bell Labs in Ohio in 1985. Many of the Bell Labs attendees of this course as well as others have contributed to the development of C++ from 1985 to 1991.
C++ is (essentially) a (big) extension of C; that is, generally any valid C program is already a valid C++ program.
C is a procedural language.
C++ adds features that make it also an object oriented language.