A sender is using selective repeat as its retransmission strategy. It sends packets 13,14,15,16,17 and does not receive an ACK for packet 13. It will retransmit which of the following when packet 13 times out 0A.13 B. 12 and 13 C. 13 and 14 D. 13, 14,15, 16, 17 Which one best summarizes the underlying idea of flow control? A. A receiver must send acks to a sender to guarantee reliability. O B. Many system designs are easier to build if you use a layered architecture. O C. There is no point in sending data faster than the network can deliver it. OD. Thene i no pontn taster hathss t. Assume that: LastSegmentSent is the sequence number of the last data packet the sender sent. LastAckReceived is the sequence number of the last acknowledged data packet. Which of these invariants must the sender of a sliding window protocol maintain? A. LastSegmentSent LastAckReceived > (Sending window size) B. LastSegmentSent+LastAckReceived> (Sending window size) C. LastSegmentSent-LastAckReceived