In the following network, frames are generated at node A and sent to node C through node B. Node A is operating at a bit rate of 50 kbps. The propagation delay is 10 ms for the link AB and 2.5 ms for the link BC. Each frame is 500 bits long. Between A and B, a sliding-window protocol with a window size of 3 is used. Node B is operating at 30 kbps. How can we avoid flooding the buffer of node B? Justify your answer with calculations. Ignore the size of the acknowledgement frames. Also assume that no errors occur during communication and no frames or acknowledgments are lost or damaged. A 3000 km- B --750 km- C