Please provide explanation

Prove explanation #include int func(int val); int x = 34; extern int z; static int doubleIt(int val) {return 2*val;} int main() {int y; y = func(x); int *a = &y; int b = doubleIt(z); printf("%d ", b); return 0;} References to which variables in the code above will need relocation during linking? a, b and y x, y and z a, b, x, y and z z x and z