Which statement could be used to explain why f(x) = 2x – 3 has an inverse relation that is a function?

Since f(x) has a domain and range of all real numbers, it's inverse also has a domain and range of all real numbers.  Furthermore since every value pair of (x,y) for f(x) is unique, its inverse will also have the inverse unique value pairs (y,x).

Ithink the answer is a