Why C is considered system programming language?
There are different programming languages. Some of them are targeted for programmers who develop application software like billing softwares, gaming application, photo editors etc. These types of programming language are known as Application Programming Language. Examples of application programming language are: C#, Java, PHP etc.
And, some of them are targeted for programmers who develop system software like operating systems, device drivers, compilers, interpreters etc. These types of programming language are known as System Programming Language. Examples of system programming language are: C, C++, GO, Rust etc.
C is not limited to developing specific types of software. Since it is not hardware or system dependent and programs written in C are portable.
C Programming language can be used to develop not only application software but also system software like Operating Systems, Compilers, Interpreters, Device Drivers etc. Due to its appropriateness for writing system software it can be called as “Systems Programming Language”.