For a system with derivative feedback, forward path transfer is G(s) = I / (s2 + s + 1) and feedback path transfer is H(s) = Ks. What is the value of K to obtain a critically-damped closed loop transient response.

(a) 0.5 (b) 0.707 (c) 1 (d) 1.414

(a) 0.5 (b) 0.707 (c) 1 (d) 1.414