The inverse of a function will also be a function if it is a One-to-One function. This means, if each y value is paired with exactly one x value then the inverse of a function will also be a function.
Option C gives us such a function, all x values are different and all y values are different. So inverse of function given in option C will result in a relation which will also be a function.
In all other options, y values are being repeated, which means they are not one to one functions.
So, the answer to this question is option C