using System;

using System.Net.Http;

using System.Threading;

using System.Threading.Tasks;

using Microsoft.Identity.Client;

​

public class Program

{

    public static async Task Main()

    {

        var cts = new CancellationTokenSource();

        var cancellationToken = cts.Token;

        var subscription = "c3c0a359-4420-4f84-8925-f642e2717296";

        var hostName = "management.azure.com";

        var apiVersion = "2020-08-01";

        var requetUrl = $"https://{hostName}/subscriptions/{subscription}?api-version={apiVersion}";

        var httpClient = new HttpClient();

        var response = await httpClient.GetAsync(requetUrl, cancellationToken);

        var authenticationParameters = WwwAuthenticateParameters.CreateFromResponseHeaders(response.Headers);

        var tenantId = authenticationParameters.GetTenantId();

​

        Console.WriteLine(tenantId);

    }

}