Given the $4-$node topology in Problem #$2,$ do the following.

$($a$)$ Give a link$-$cost change for either $c(u,v)$ or $c(u,w)$ such that $u$ will inform its neighbors of a

new minimum$-$cost path to $x$ as a result of executing the distance$-$vector algorithm.

$($b$)$ Give a link$-$cost change for either $c(u,v)$ or $c(u,w)$ such that $u$ will not inform its neighbors

of a new minimum$-$cost path to $x$ as a result of executing the distance$-$vector algorithm.