问题详情

执行下列程序后，输出结果为()。 public class Test { public static void main (String[] args) { StringBuffer sb ＝ new StringBuffer("北京 2008" ); System. out. println ("length ＝" + sb. length () ); } }
A．length = 8
B．length = 10
C．length = 6
D．length = 20请帮忙给出正确答案和分析，谢谢！