[20 Points] Question 4: Ethernet uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) for its media access-control. Thus, each node listens while transmitting a frame to detect when a frame collided with another frame transmitted by another node. However, if a frame is too short, a node sometimes cannot detect a collision. a. What can happen when a frame is too short? b. Assume a signal can propagate through a copper Ethernet wire at 1.8108m/s. If the maximum distance between any two nodes is 900m and you use a 10-Mbps Ethernet, what is the minimum frame size needed to detect collisions? c. If an Ethernet wire is made of a better material such that a signal can propagate through the wire at 2.5108m/s, what is the new minimum frame size for your network? d. If the maximum distance between any two nodes increases to 1800m, what is the new minimum frame size for your network using a copper Ethernet wire? e. Suppose you upgrade your network from a 10-Mbps Ethernet to a 100-Mbps Ethernet. How can you support this new 100-Mbps Ethernet without changing the minimum frame size or moving the nodes