I used to be a fan of style C, but these days, I prefer either A or B, with the condition that no MinorFunction should be less than 5 lines of code. If a function is that small, and it's called from only one place, then it doesn't need to be a function.

Using A or B results in self-documenting code and I think DOES (or at least, CAN) improve readability. It also can help reduce excessive nesting of code.