32 A security firm needs to connect alarm systems to the firm’s main control site from five potential trouble locations. Since the systems must be fail-safe, the cables must be run in special pipes. These pipes are very expensive but large enough to simultaneously handle five cables (the maximum that might be needed). Use the minimal-spanning tree model to find the minimum total length of pipes needed to connect the locations shown in Figure 22 . Node 6 represents the main control site.