A classical negative feedback control system has the following transfer functions:

$G_1(s)=\frac{K_1}{{}_{1}s+1}$

$G_2(s)=\frac{K_2}{{}_{2}s+1}$

Which one does identify the correct closed$-$loop relationship?

$($A$)Y(s)=\frac{\frac{K_2}{{}_{2}s+1}[\frac{K_1}{{}_{1}s+1}R(s)+L(s)]}{1+\frac{K_2}{{}_{2}s+1}\frac{K_1}{{}_{1}s+1}H(s)}$

$($B$)Y(s)=\frac{\frac{K_2}{{}_{2}s+1}[\frac{K_1}{{}_{1}s+1}R(s)+1]}{1+\frac{K_2}{{}_{2}s+1}\frac{K_1}{{}_{1}s+1}H(s)L(s)}$

$($C$)Y(s)=\frac{\frac{K_1}{{}_{1}s+1}[\frac{K_2}{{}_{2}s+1}R(s)+L(s)]}{1-\frac{K_1{K}_2}{{}_1{}_2+1}H(s)}$

$($D$)Y(s)=\frac{\frac{K_1}{{}_{1}s+1}\frac{K_2}{{}_{2}s+1}R(s)+L(s)}{1+\frac{K_2}{{}_{2}s+1}H(s)}$