The closed-loop transfer function \(\frac{{C\left( s \right)}}{{R\left( s \right)}}\) of the system represented by the signal flow graph as shown in figure is
1
\(\frac{{{G_1}{G_2}{G_3}{G_4}}}{{\left( {1 + {G_1} + {G_2}} \right)}}\)
2
\(\frac{{{G_1}{G_2}{G_3}{G_4}}}{{\left( {1 + {G_3} + {G_4}} \right)}}\)
3
\(\frac{{{G_1}{G_2}{G_3}{G_4}}}{{\left( {1 + {G_1} + {G_2}} \right)\left( {1 + {G_3} + {G_4}} \right)}}\)
4
\(\frac{{{G_1}{G_2}{G_3}{G_4}}}{{\left( {1 + {G_1}{G_2}} \right)\left( {1 + {G_3}{G_4}} \right)}}\)