using System;

abstract class A$\{$

private int $x$;

public

$x=7$;

$\}$

public $A($int y$)\{$

$x=y$;

$\}$

public abstract int do$\_$stuff$1()$;

public abstract int do$\_$stuff$2()$;

$\}$

class

public B$()$ : base$(7)\{$

$\}$

public B$($int y$)$ : base $($y$)\{$

$\}$

public override int do$\_$stuff$1()\{$

return $4$

$\}$

public override int do$\_$stuff$2()\{$

return $4$

$\}$

$\}$

class MainClass $\{$

public static void Main $($string$[]$ args$)\{$

$B$ myB $=$ new $B(5)$;

$\}$

$\}$

No$,$ class A cannot have a constructor since it's abstract$.$

No$,$ class B can't have a constructor since it's inheriting from an abstract class A $.$

No$,$ you can't use super$/$base to call a constructor in an abstract class.

Yes