Which lines fail to compile? 

A. Only line x

B. Only line y

C. Both lines x and y

D. The code compiles.

package armory; import java.util.function. *; interface Shield { void protect(); } class Dragon { int addDragon (Integer count) { return ++count; } } public class Sword { public static void main(String[] knight) { var dragon = new Dragon (); Function func = Shield::protect; // line x UnaryOperator op = dragon:: addDragon; // line y } }