Python is a programming language, or a set of rules that can be used to create programmes. This language has various implementations.
Whatever implementation you choose, they all accomplish the same thing: they take the text of your programme and interpret it, executing its instructions. They do not compile your code into C or any other language.
The first Python implementation, written in C, is CPython. (The "C" in "CPython" refers to the language used to create the Python interpreter.)
Jython is the same language as Python, however it is written in Java.
C# was used to create the IronPython interpreter.
PyPy is another Python interpreter written in Python.