The open-loop transfer function of a unity negative feedback control system is given by

\[
\mathrm{G}(s)=\frac{\mathrm{K}(s+2)}{[(s+1)(s-7)]}
\]

For \(\mathrm{K}>6\), the stability characteristics of the open-loop configuration and closed-loop configuration of the system are respectively
(a) stable and stable
(b) unstable and stable
(c) stable and unstable
(d) unstable and unstable