Please write this in C#

A 4-none Network System consists of 4 nodes connected together. The connections among these four nodes vary depending on the network topology. In the following figure, three different network topologies are shown: In the project, we are particularly interested in the length connecting among two different nodes. For example, to connect node B and node D, the "complete" topology provides the shortest path if all links have the same length. If various lengths are assigned to different links, then estimations among each pair of nodes will be needed before the shortest path can be determined. For the 4-node network system, there are (4 2) = 6 possible pairs of nodes, without considering the directions, as listed below: A-B A-C A-D B-C B-D C-D Design and develop a C# project, utilizing the concept of object-oriented programming, to assess the shortest distance between any selected two nodes (chosen by the users) under each topology, and determine which topology will provide the shortest path. Here are the requirements for the project: Encapsulation, Inheritance, Polymorphism and Composition must be applied Model each link as an object of a class named "Link", with length being a private data member, and "get" and "set" public methods to read and write the length. Specify the 4-node Network System as an abstract class, with pure virtual functions for calculating the length among nodes Each topology is modeled as a derived class of the 4-node Network System, where the links and the corresponding lengths can be assigned In the driver, declare the three different networks, with lengths of your choices. Figure out which one has the shortest path among two nodes, chosen by the user