Which lines of code are valid declarations of a native method when occurring within the declaration of the following class？（）   
public class Qf575 {  
// insert declaration of a native method here 
 }  

What will be written to the standard output when the following program is run？（）  
class Base {  int i；  Base（） {  
add（1）；  
}  
void add（int v） {  i += v；  }  
void print（） {  System.out.println（i）；  }  
}  
class Extension extends Base {  Extension（） {  add（2）；  }  
void add（int v） {  i += v*2；  }  }  
public class Qd073 {  
public static void main（String args[]） {  bogo（new Extension（））；  }  
static void bogo（Base b） {  b.add（8）；  b.print（）；  
}  
}