Consider the system described by following state space equations\(\left[ {\begin{array}{*{20}{c}}{{{\dot x}_1}}\\{{{\dot x}_2}}\end{array}} \right] = \left[ {\begin{array}{*{20}{c}}0&1\\{ - 1}&{ - 1}\end{array}} \right]\left[ {\begin{array}{*{20}{c}}{{x_1}}\\{{x_2}}\end{array}} \right] + \left[ {\begin{array}{*{20}{c}}0\\1\end{array}} \right]u;y = \left[ {\begin{array}{*{20}{c}}1&0\end{array}} \right]\left[ {\begin{array}{*{20}{c}}{{x_1}}\\{{x_2}}\end{array}} \right]\)If u is unit step input, then the steady state error of the system is

• A. 0
• B. 1/2
• C. 2/3
• D. 1