请考虑以下C#代码

var L1 =
Task.Run(() =>
{
    return Task.Run(() =>
    {
        return Task.Run(() =>
        {
            return Task.Run(() =>
            {
                return new Dummy();
            });
        });
    });
});

var L2 =
Task.Run(async () =>
{
    return await Task.Run(async () =>
    {
        return await Task.Run(async () =>
        {
            return await Task.Run(async () =>
            {
                return new Dummy();
            });
        });
    });
});

var L3 =
Task.Run(async () =>
{
    return Task.Run(async () =>
    {
        return Task.Run(async () =>
        {
            return Task.Run(async () =>
            { …