** Using WeBWorK **

Is it possible to, depending on a student's answer to a pop up, change the way the rest of the question is rendered?

For example, the following question prints two matrices and expects the student to determine whether their product is defined.  Since the answer in this case is yes, once they correctly answer the question, I'd like to ask them also to specify the dimensions of the product.  In order to not sway their answer, ideally I'd like ask them for the dimensions only if they have concluded that the product is defined.

DOCUMENT();

loadMacros(
  'PGstandard.pl',
  'PGML.pl',
  'MathObjects.pl',
  'parserPopUp.pl'
);

$A = Matrix([[1,2,3,4],[1,2,3,4],[1,2,3,4]]);
$B = Matrix([[1,2],[1,2],[1,2],[1,2]]);

$popup = DropDown(
  ["undefined", "defined"],
  "defined",
  placeholder => 'Select one'
);

BEGIN_PGML

[`[$A][$B]`] is [_]{$popup}.

END_PGML

ENDDOCUMENT();