class IDCard
    {
        public string Gender { get; set; }
        public string HairColor { get; set; }
        public string Weight { get; set; }
        public string DateOfBirth { get; set; }
        public string Email { get; set; }
    }

    class HairColor { }
    class Weight { }
    class Email { }
    class Age : IComparable<Age>
    {
        public int CompareTo(Age other) {...}
    }

    struct Optional<T> /* Наивная реализация для примера */
    {
        public bool HasValue() {...}
        public T Value { get; set; }
    }

    class Person : IComparable<Age>
    {
        public HairColor HairColor { get; set; }
        public Weight Weight { get; set; }
        public Age Age { get; set; }
        public Email Email { get; set; }
        public int CompareTo(Age other) {...}
    }

    class Male : Person { }
    class Female : Person { }
    class Adult<T>  where T : IComparable<Age>
    {
        public T Value { get; private set; }
        public static Optional<Adult<T>> Create(T arg){...}
    }
    
    class UnderAge<T> where T : IComparable<Age>
    {
        public T Value { get; private set; }
        public static Optional<UnderAge<T>> Create(T arg) {...}
    }

    class Blondie { public Blondie(Adult<Female> woman) { } }
    class PlumpWoman { public PlumpWoman(Adult<Female> woman) { } }
    class SexyWoman { public SexyWoman(Adult<Female> woman) { } }
}

class Program
{
    static bool SendEmail(Email email, UnderAge<Age> age) => true;
    static bool PlayWith(UnderAge<Male> boy) => true;
    static bool AskMath(Blondie woman) => true;
    static bool AskRecipe(PlumpWoman woman) => true;
    static bool FindWife(SexyWoman woman) => true;

    static Optional<Person> Parser(IDCard card) => new Optional<Person>(/*...*/);

    static void Main(string[] args)
    {
        var rawData = new IDCard[10];
        var persons = rawData
            .Select(Parser)
            .Where(p => p.HasValue())
            .Select(p => p.Value)
            .ToArray();

        var children = persons.Select(UnderAge<Person>.Create)
            .Where(p => p.HasValue()).Select(p => p.Value)
            .ToArray();

        var q1 = children.Select(p => new { Email = p.Value.Email, Age = UnderAge<Age>.Create(p.Value.Age).Value })
            .Select(item => SendEmail(item.Email, item.Age));

        var q2 = children
            .OfType<UnderAge<Male>>()
            .Select(PlayWith)
            .ToArray();

        var women = persons.Select(Adult<Person>.Create)
             .Where(p => p.HasValue())
             .OfType<Adult<Female>>()
             .Select();

        var q3 = women.Select(Blondie.Create)
             .Where(p => p.HasValue())
             .Select(p => p.Value)
             .Select(AskMath)
             .ToArray();

        /* Остальные методы очевидны из q3 */  
    }
}