Which of the following statements is incorrect about a delegate?

1. Delegates are not type-safe.
2. Delegate is a user-defined type.
3. Only one method can be bound with one delegate object.
4. Delegates can be used to implement callback notification.
5. Delegates permit execution of a method on a secondary thread in an asynchronous manner.

class Sample
{
    public int MyFun(int i)
    {
        Console.WriteLine("Welcome to CuriousTab.com !" );
        return 0;
    }
}

delegate void del(int i);
Sample s = new Sample();
deld = new del(ref s.MyFun);
d(10);

delegate int del(int i);
Sample s = new Sample(.);
del = new delegate(ref MyFun);
del(10);

Sample s = new Sample();
delegate void del = new delegate(ref MyFun);
del(10);

delegate int del(int i);
del d;
Sample s = new Sample();
d = new del(ref s.MyFun);
d(10);

1. Stack
2. Tree
3. SortedDictionary
4. SortedArray

public class TestCuriousTab
{
    public void TestSub<M> (M arg)
    {
        Console.Write(arg);
    }
}
class MyProgram
{
    static void Main(string[] args)
    {
        TestCuriousTab tab = new TestCuriousTab();
        tab.TestSub("CuriousTab ");
        tab.TestSub(4.2f);
    }
}

public class Generic<T>
{
    public T Field; 
    public void TestSub()
    {
        T i = Field + 1;
    }
}
class MyProgram
{
    static void Main(string[] args)
    {
        Generic<int> gen = new Generic<int>();
        gen.TestSub();
    }
}