1. public class Test {  2. public static void main （String []args）  {  3. unsigned byte b = 0；  4. b--；  5.     6.   }  7. }   What is the value of b at line 5？（）  

• A、 -1
• B、 255
• C、 127
• D、 Compilation will fail.
• E、 Compilation will succeed but the program will throw an exception at line 4.