Consider a system represented by the block diagram shown below. Which of the following signal flow graphs represent(s) this system? Choose the correct option(s).

In the following block diagram, R(s) and D(s) are two inputs. The output Y(s) is expressed as Y(s) = G$$_1$$(s)R(s) + G$$_2$$(s)D(s).

G$$_1$$(s) and G$$_2$$(s) are given by

The block diagram of a feedback control system is shown in the figure.$$ \text { The transfer function } \frac{Y(s)}{X(s)} \text { of the system is } $$