Questions $(14)$ through $(16)$ pertain to the following graph:

Use Kruskal's algorithm to find a minimum$-$cost spanning tree in the graph above. What is the cost of

the tree that you found? The edge lengths in the graph are

$1,1,2,2,3,3,4,4,5,5,6,6,7,7$

and note that all vertices are on the "outside" of the graph. There is no vertex where at the one location

where two edges cross on the interior of the graph.

$($a$)12$

$($c$)17$

$($b$)14$

$($d$)21$

Ignoring the weights associated to each edge $($or link$),$ what is the diameter of this graph?

$($a$)2$

$($c$)3$

$($b$)4$

$($d$)5$

What is the redundancy of the graph $($or network$)$ above?

$($a$)4$

$($c$)6$

$($b$)5$

$($d$)7$