using C# how do I construct custom JSON response

using System;
using System.Collections.Generic;
using Newtonsoft.Json;

public class InvalidPolicy
{
    public string OldNumber { get; set; }
    public string NewNumber { get; set; }
}

class Program
{
    static void Main()
    {
        // Create your DataTable (assuming you already have it)
        DataTable accountRecords = new DataTable();
        // ... Add data to the DataTable ...

        List invalidPolicies = new List();

        foreach (DataRow row in accountRecords.Rows)
        {
            invalidPolicies.Add(new InvalidPolicy
            {
                OldNumber = row["OldNumber"].ToString(),
                NewNumber = row["NewNumber"].ToString()
            });
        }

        var result = new
        {
            InvalidPolicies = invalidPolicies,
            ReceivedCount = invalidPolicies.Count,
            SuccessCount = 0, // Set the actual success count
            FailedCount = 0, // Set the actual failed count
            Notices = new List