Given the following code, write a line of code that, when inserted at the indicated location, will make the overriding method in Extension invoke the overridden method in class Base on the current object.  
class Base {  
public void print() {  
System.out.println("base");  
}  
}  
class Extention extends Base {  
public void print() {  
System.out.println("extension");  
// insert line of implementation here  
}  
} 
 public class Q294d {  
public static void main(String args[]) {  
Extention ext = new Extention();  
ext.print();  
}  
}  
Fill in a single line of implementation.（）