Difference between these two NSString methods

Question

So I just got asked this at an interview today and after some googling am still unable to figure out the answer (in fact I couldn\'t even find any code at all which used the

Answer 1

The only thing I can imagine is that:

1. Won't allocate memory since it is not made with alloc. It is a constant (an empty string) made by the system and doesn't need to be released.

2. You allocate the memory for the NSString yourself which means you have to keep track if the NSString still 'lives' or not when you are done with it, and thus need to release it.