public class Foo implements java.io.Serializable { Line1. private int x; Line2. public int getX() { return x; } Line 3.publicFoo(int x){this.x=x; } Line 4. private void writeObject( ObjectOutputStream s) Line 5. throws IOException { Line 6. // insert code here Line 7. } Line 8. } Which code fragment, inserted at line Line 6, will allow Foo objects to be correctly serialized and deserialized? A. s.writeInt(x); B. s.serialize(x); C. s.writeObject(x); D. s.defaultWriteObject();