On a more serious note, learn everything and decide what's most appropriate.
C is nice for fairly low-level applications development - for a desktop program, I'd usually expect it to be written in C or C++ (C is, in most regards, a subset of C++ so you can learn C first and then start using C++ features or just go for full-on C++.)
C++ is similar to Java because Java was heavily influenced by C and C++, and they're both object-oriented.
Python is generally a nice language to learn with because it's syntax is similar to English in a lot of respects. It removes most of the brackets and is picky about newlines, tabs and spaces, but usually an IDE or editor (Pycharm <3) will tell you about that. There's a nice document called PEP-8 that documents the standard.
Java generally scales well for large web applications, although people seem to see it as fairly antiquated these days. That said, it's a lovely language to write in, and the standard library and documentation makes it pretty easy to do almost anything if you want to.