Considering the following process in the selective repeat pipelined protocol, what will happen when ACK2 arrives at the sender? The sender window will cover 6-9 and the sender will transmit pkt6. The sender will ignore ack 2 . The sender window will cover 3-6. The sender will re-transmit pkt3. Consider the graph shown below and the use of Dijkstra's algorithm to compute a least cost path from a to all destinations. Suppose that nodes b and d have already been added to N. What is the path cost to the next node to be added to N ? 5 9 7 6 4 8