There is literally no place where C has no viable alternative.
Furthermore most environments that seem to have only C are a Gcc target, and then you have access to all the other languages Gcc can compile, without a detour to C.
Transcribing leads to a horrible debug experience. Immature languages maintained by a single/few are a no-go. Your team already knows C and is good at it, finding new programmers is easy.
You don't want another language, even if it's supported by GCC. If you want anything from C, then it's more safety guarantees. And C is flexible enough to run a better type system on top of it, e.g. look at what the kernel community is doing with `sparse`.
But to insist there is no alternative is just untrue, and (after you have been corrected) dishonest.