using System;

using System.Linq;

using System.Collections.Generic;

using System.Threading.Tasks;

public class Program

{

    public static async Task<int> SomeAsync()

    {

        return await Task.Run(() => 2);

    }

    public static void Main()

    {

        List<(int, string)> lst = new()

        {

            (1, "b"),

            (10, "d"),

            (100, "f"),

            (1000, "h"),

        };

        List<string> r = lst

            .Select(async x =>

            {

                var (a, b) = x;

                int foo = await SomeAsync();

                return a > 99 ? b : null;

            })

            .Select(x => x.Result)

            .Where(x => x != null)

            .ToList();

        foreach (var x in r)

        {

            Console.WriteLine(x);   

        }

    }

}