Which of the following snippets are the correct way to convert a Single into a String?

1. Single f = 9.8f; 
   String s;
   s = (String) (f);

2. Single f = 9.8f; 
   String s;
   s = Convert.ToString(f);

3. Single f = 9.8f; 
   String s;
   s = f.ToString();

4. Single f = 9.8f; 
   String s;
   s = Clnt(f);

5. Single f = 9.8f; 
   String s;
   s = CString(f);