If you want to learn systems programming, I can recommend learning C. If you want to learn a programming language which allows systems programming, I guess Rust is not a bad choice. But it might be less helpful if the systems basics are unknown.

I'm an industrial equipment programmer, so I do see C quite often. Actually, aside from C, it's just that when I first learned programming in college, I started with C. I thought that was only natural, but I guess I didn't explain enough. Inside my own head, C just feels like a given.