The overall transfer function of a second order control system is given by\(\frac{{C\left( s \right)}}{{R\left( s \right)}} = \frac{2}{{{s^2} + 3s + 2}}\)The time response of this system, when subjected to a unit step response is

• A. 1 – e-2t + 2e-t
• B. 1 + e-2t + 2e-t
• C. 1 – 2e-t + e-2t
• D. 1 + e-2t