Need help with discrete structures

Let f be a function from the set A to the set B. Let S be a subset of B. We define the inverse image of S to be the subset of A whose elements are precisely all pre-images of all elements of S. We denote the inverse image of S by f1(S), so f1(S)={aAf(a)S}. Let f be the function from R to R defined by f(x)=x2. Find the value of given functions. f1({xx>4}) Multiple Choice f1({xx>4})={xx>2} f1({xx>4})={xx>2x4})={xx2} f1({xx>4})={xx4})={xx>2x