$\backslash$table$[[\backslash$table$[[$protected int $x$;$],[$public A $($int x$)],[$this$.$x $=x$;$]],,\backslash$table$[[$public class B extends A$],[$protected int x;$],[$public B $($int x$)\{],[$this$.$x $=x$;$],[\}]]]]$

Figure $5$

$19.$ Consider Figure $5.$ How would one refer to the attribute $x$ in A from within a method of $B?$

$($a$)$ this.x

$($b$)$ super. $x$

$($c$)(($A$)$ this$).$x

$($d$)$ Both $($b$)$ and $($c$).$

$($c$)$ It is impossible to refer to $x$ in A from the class $B.$

$20.$ Consider Figure $5.$ The code does not compile. Which of the following lines will make the corle compile?

$($a$)$ The first line of public A $($int $x)$ shonld be super $(x)$:

$($b$)$ The first line of public $B($int $x)$ should be super $(x)$ :