MyClass.cs

namespace ProjectDSA
{
    internal class MyClass
    {
        // Base class for A, B, C
        public class Class_Lst
        {
            public string Name { get; set; }
            public string Gender { get; set; }
            public int Age { get; set; }

            // Build sentence for the selected property
            public string View(string option)
            {
                switch (option)
                {
                    case "Name":
                        return $"Hello, my Name is: {Name}.";
                    case "Gender":
                        return $"Hello, my Gender is: {Gender}.";
                    case "Age":
                        return $"Hello, my Age is: {Age}.";
                    default:
                        return string.Empty;
                }
            }
        }

        // 3 classes: A, B, C
        public class ClassA : Class_Lst { }
        public class ClassB : Class_Lst { }
        public class ClassC : Class_Lst { }
    }
}