im getting error in delegate

public  class dept
    {
        public int deptid { get; set; }
        public string dname { get; set; }
        public int salary { get; set; }
        public int Experience { get; set; }
    }


    public class demp
    {
        static void Main(string[] args)
        {
            List<dept> de = new List<dept>();
            de.Add(new dept() { deptid = 1, dname = "k", salary = 8909, Experience = 2 });
            de.Add(new dept() { deptid = 1, dname = "l", salary = 8909, Experience = 3 });
            de.Add(new dept() { deptid = 1, dname = "m", salary = 8909, Experience = 4 });
            de.Add(new dept() { deptid = 1, dname = "n", salary = 8909, Experience = 5 });

            deptl(de, x => x.Experience > 2);
        }

        public static void deptl(List<dept> ldept,del sk)//getting error in dept1
        {
            foreach (dept item in ldept)
            {
                if (sk(item))
                {
                    Console.WriteLine(item.dname + " IsPromoted");
                    Console.ReadLine();
                }
            }
        }

        delegate bool del(dept d);
    }
}