A function is an algebraic expression that maps the transformation from one group of numbers to the other. The group of numbers which is used as an input is called the domain, while the group of number used as an ouput is called range of the function. The inverse of a function is the operation that does the oposite path, the domain and range are switched in such a way that the domain of the inverse is the range of the original and the range of the inverse is the domain of the original. With this in mind we can say that the correct answer is the first option.