Please give detailed answer...

Consider the following connected weighted undirected graph representing costs (for the Internet provider) of sending messages along the edges representing connections. The rows and columns (corresponding to the nodes, or vertices, in the network) are numbered from 0 to 5. For example, the cost of sending a message from vertex 1 to vertex 3 is 9 (and the same, for sending from d to b). The" entries in this matrix mark a lack of a direct connection between the corresponding pair of vertices (think that the cost of sending a message along those missing edges is an infinity) 5 9-- 15 6 -7 5 15 - 8 To minimize the total cost of the network, the Internet provider maintains the minimum number of edges to keep the network connected -in fact, it maintains the MST of the network. The operation cost for the company is equal to the cost of this MST. Now, the Internet provider decided, that for technical reasons, the direct connection (edge) between vertex 3 and 4 (the cost is 15) must be a part of the tree. So, the network contains now the edge 3-4 and additionally an appropriate selection of five additional edges to minimize the cost of such a constrained tree. What is the cost to the minimal cost tree before introducing the condition that the edge 3-4 is a part of the tree? answer:cost(MST)- What is the cost of the minimal cost tree with the edge 3-4? answer: cost(MST that contains 3-4)- Hint: To what value can we tentatively change the weight of the edge so it is immediately selected by Kruskal's algorithm into MST