Consider the network of Fig. $5-15($a$).$ Imagine that one new line is added, between F and G$,$ but the sink tree of Fig. $5-15($b$)$ remains unchanged. What changes occur to Fig. $5-15($c$)?($a$)$

$($b$)$

$($c$)$

Figure $5-15.$ Reverse path forwarding. $($a$)$ A network. $($b$)$ Sink tree for router I.

$($c$)$ The tree built by reverse path forwarding from I.