1.b. NID Number
Birth ID
3.a.) Members of a class are private by default and members of struct are public by default.
            As the attributes of the person such as his/her personal information should be private so I will choose class.
            b. class Test
            {
                int name,age,date_of_birth,fathers_name,mothers_name,address,nid_no;
                void set_name(string name)
                {
                    this.name=name;
                }
                int set_nid(int)
                {
                    this.nid_nod=nid;
                }
                void set_age(int age)
                {
                    this.age = age;
                }
                void set_address(string address )
                {
                    this.address=address;
                }
                void set fathers_name( string name )
                {
                    this.fathers_name = name ;
                }
                void set mothers_name( string name )
                {
                    this.mothers_name = name ;
                }
                int get_nid()
                {
                    return this.nid_no;
                }
            public :
                int get_age()
                {
                    return this.age;
                }
                string get_name()
                {
                    return this.name;
                }
                string  get_address()
                {
                    this.address;
                }
                string get_fathers_name( )
                {
                    this.fathers_name;
                }
                string  get_mothers_name()
                {
                    this.mothers_name ;
                }



            };