If the closed loop transfer function \(\mathrm{T}(s)\) of a unity negative feedback system is given by;

\[
\mathrm{T}(s)=\frac{a_{n-1} s+a_{n}}{s^{n}+a_{1} s^{n-1}+\ldots \ldots . .+a_{n-1} s+a_{n}}
\]

then the steady state error for a unit ramp input is:
(a) \(\frac{a_{n}}{a_{n-1}}\)
(b) \(\frac{a_{n}}{a_{n-2}}\)
(c) \(\frac{a_{n-1}}{a_{n-2}}\)
(d) zero