Asking about a programming language while not precising the context, is surely a wrong idea.

A language for doing what: softwares for users? server-side services? science? etc… C is “the” evolved language that is the closest to assembly, and you know that assembly is the language of the hardwares, right?

Therefore the C is right now the number one language for coding operating systems (core, libraries, drivers, etc), and always will be.

Unless humanity finds a way to make a more proper “close to assembly” language, like maybe Google’s Go language