4.(8 points) Consider two nodes A and B connected via an Ethernet bus of 10 Mbps. Suppose that the two nodes are the only nodes, and that the propagation delay between them is 224 bit times Suppose that both nodes each has a frame to send, and at time t-0 they both start transmitting. After collision. node A chooses KA-0 and node B chooses KB-1. Recall that, in the CSMA/CD algorithm, right after detecting a collision, a node must send a jam signal of 48 bit times. The CSMA/CD algorithm also requires that a node, having a frame to send, sense the bus idle for 96 bit times before it can transmit. The frame length is 1000 bits. All answers must be in microseconds (a) (2 points) At what time does the collision occur (in microseconds)? time microseconds (b) (2 points) At what time does the bus become idle (in microseconds)? time microseconds (c) (2 points) At what time does A begin retransmission (in microseconds)? time microseconds (d) (2 points) At what time does A's frame get successfully delivered to B in microseconds)