b) Using the network shown below and Dijkstra's algorithm find the least cost path from A to B. State the actual path that a packet would follow and identify the final cost. Show all your workings for full marks. (15 marks) A c) Consider a simple network communication, where four packets are sent to a receiver. Packets 1, 3 and 4 arrive correctly, but packet 2 is sent with an error. Describe using both text and a timing diagram what happens during the exchange of packets when the Selective-Reject mechanism is in place. (15 marks) d) What bits need to be added to the following bit sequence if a simple parity check with odd parity is used to check for errors? Use blocks of seven data bits and clearly indicate where you have added the extra bits used for error checking, 1011101110011000100101101111