Unit step response of the system described by difference equation y(n) + y(n - 1) = x(n) is

• A. \(\dfrac{z^2}{(z+1)(z-1)}\)
• B. \(\dfrac{z}{(z+1)(z-1)}\)
• C. \(\dfrac{(z+1)}{(z-1)}\)
• D. \(\dfrac{z(z-1)}{(z+1)}\)