This should not be a surprise. Consider what happens on a modern CPU after the preprocessors do their job, after the compilers do their job, when you're right down to machine code: the bare metal!
But really, how bare is that metal? Not at all.
Your so-called "machine language" just turns out to be another high level language that the CPU itself compiles down to the actual internal instructions that it executes, instructions that look nothing like what you thought was the machine language.
If you want a binary executable, yes. But that's sort of a tautology: If a program produces some output (like C source code or a binary), you usually run it because you intend to do something with its output later (like compile it or interpret it, or execute it on the machine if it's a binary).
Yes, either another compiler to translate it to machine code, or a C interpreter. Years ago, for example, there was a C interpreter that went by the name "Saber C," if memory serves.
