When a unit ramp input is applied to the unity feedback system having closed loop transfer function $\frac{C(s)}{R(s)}=\frac{Ks+b}{s^{2}+as+b}, (a>0, b>0, K>0)$, the steady state error will be
- $0 \\ $
- $\frac{a}{b} \\$
- $\frac{a+K}{b} \\$
- $\frac{a-K}{b}$