If you write something in Objective-C, it will become an executable when you compile it, no different than if you do it in C or C++. Since all the native Mac libraries are designed for Obj-C, why do you want to avoid it? Obj-C is a very small superset of C, not that much different really, except for the object system. You could say that if C is English and C++ is English-French pidgin with random additions of Chinese and Navajo (for expressivity, you know), Objective-C is kind of like Scots - very close, even if few people not familiar with it understand it...
I didn't answer the actual question - @Shyam took care of that :D