Given the example network layout: Furthermore assume that: - FTU A consists of three SRUs (node 1, node 2, node 3) - FTU B consists of two SRUs (node 4 and node 5) - FTU C consists of two SRUs (node 6 and node 7) - FTU D consists of two SRUs (node 8 and node 9) - FTU E consists of two SRUs (node 10 and node 11) - The "smart sensors" (sensor 1, sensor 2, sensor 3, sensor 4, sensor 5) on the TTP/A bus are connected to FTU D and are all identical and thus redundant sensors. - The "smart sensors" (sensor 6, sensor 7, sensor 8, sensor 9, sensor 10) on the TTP/A bus are connected to FTU E and are all identical and thus redundant sensors. The fault-tolerance mechanism that is assumed in the above problem is fail-silent operation. For the system to work at least one SRU of in every FTU (A, B, C, D and E) and one sensor in each TTP/A bus must function properly. Draw the fault-Tree of the above network where the top-level event is a system level failure.