A negative unity feedback system has a loop transfer function,

$L(s)=D(s)G(s)=\frac{10(s+1)}{s(s+5)}$

The steady$-$state error to a desired input $r(t)=(5+t)u(t)$ with $u(t)$ as a step function is

a$.,e_{ss}=$

b$.,e_{ss}=0$

c$.,e_{cc}=0\mathrm{.}5$