Graph for Dialogue system

public class NodeBase {
 private static List<NodeBase> allNodes = new List<NodeBase>();
 public NodeBase() {
  allNodes.Add(this);
 }
 ~NodeBase() {
  allNodes.Remove(this);
 }
}

public class NodeLink {
 public string text;
 public NodeDialog next;
 public UnityAction LinkAction;
}

public class NodeDialog : NodeBase {
 public string text;
 public NodeLink[] answers;
 public UnityAction DialogAction;
}