下面程序的执行的结果是______。public class ex48{ public static void main(String[] args) { String s1 = "abc" + "def"; String s2 = new String(sl); if(s1 == s2) System.out.println ( "== succeeded"); if (s1. equals (s2) ) System.out.println (".equals () succeeded"); }}

A．== succeeded

B．.equals() succeeded

C．== succeeded

D．不输出任何结果 .equals() succeeded