单项选择题
What is the result as follows？（）
A.5，6 B.5，5 C.6，5 D.6，6
A.00 B.0001 C.000120 D.00012021 E.Compilation fails. F.An exception is thrown at runtime.
A.2 B.3 C.1，2 D.2，3 E.1，2，3
