在下列程序的空白处，应填入的正确选项是( )。
Import java.io.*;
Pulilc class ObjectStreamTest
Publilc static void main(string args[])throws IOException
ObjectoutputStream oos=new ObjectOutputStream
(new FileOutputStream("serial.bin"));
Java.util.Date d=new Java.util.Date();
Oos______(d);
ObjectInputStream ois=
new ObjectInputStream(new FileOutputStream("serial.bin"));
try
java.util.date restoredDate=
(Java.util.Date)ois.readObject();
System.out.println
("read object back from serial.bin file:"
+restoredDate);

Catch(ClassNotFoundException cnf)
System.out.println("class not found");

A．WriterOhject

B．Writer

C．BufferedWriter

D．writerObject