C# Pa check nitong code ko, mamaya na kase submission

[Chunchunmaru]

Tama ba tong ginawa ko, number 4 at 5 etong code, kaso di ko sure kung tama.

using System;
using System.IO;
using System.Linq;
using System.Collections.Generic;

namespace Average
{
    
   public delegate string name(string firstName, string secondName);
  
    }
    
    public class Program
    {
        static string lastName;
        static string firstName;
        
    public static string FName(string firstName)
    {
        return firstName;
    }
    
    public static string LName(string lastName)
    {
        return lastName;
    }
        
        public static void Main()
        {
            
        }
    }

Yung problem

Paki correct balang kung saan ako mali