Let a, b, x and y be real numbers such that a-b = 1 and y ? 0. If the complex number z = x + iy satisfies Im((az +b)/(z+1)) = y, then which of the following is(are) possible value(s) of x?

(a) -1 + ?(1 – y²)

(b) -1 – ?(1 – y²)

(c) 1 + ?(1 + y²)

(d) 1 – ?(1 + y²)