Consider:

class A

$\{$

public void doA$()$

$\{$

$\}$

$\}$

class B extends A

$\{$

public void doB$()$

$\{$

$\}$

$\}$

Which of the following are allowed?

Group of answer choices

A x $=$ new A$()$;

x$.$doA$()$;

B x $=$ new B$()$;

x$.$doB$()$;

A x $=$ new A$()$;

x$.$doB$()$;

B x $=$ new B$()$;

x$.$doA$()$;