下述哪一项能够将文本“<end>”加到文件file.txt的末尾?(    ) 
a.OutputStream out=new FileOutputStream("file.txt");
  Out.writeBytes("<end>/n");
b.OutputStream OS=new FileOutputStream("file.txt",true);
  DataOutputStream out=new DataOutputStream(os);
  out.writeBytes ("<end>/n");
c.OutputStream OS=new FileOutputStream ( "file.txt");
  DataOutputStream out=new DataOutputStream(os);
  out.writeBytes("<end>/n");
d.OutputStream OS=new OutputStream("file.txt",true);
  DataOutputStream out=new DataOucputStream(os);
  out.writeBytes ("<end>/n");哪一项是对的啊?太混淆不清了!