Aside from some syntax around function prototypes, it's really not, unless you are counting "people tend to use certain things less often" as how you're counting that difference.
If you're counting the language by "how many pages of specification" it takes up, perhaps. To me is the language is really like the many features it had when it came out, and then the standard library improvements since then have been "string routines" and then "more string routines" and then "atomics, and also some string routines". Now C++, that's a language that has changed a huge deal–your C++03 code is obviously out-of-place in a C++11 codebase, but nobody will bat an eye if you drop some C89 code in a C11 project.
I've used C for long enough to meaningfully contribute to this conversation. And yes, by my definition C takes much of its inspiration from B, although there are enough differences that I would not claim that B is some sort of release of C.
