The following predicate logic formula is invalid:

$8$x; $9$y:P $.$x; y$/!9$y;$8$x:P $.$x; y$/$

Which of the following are counter models for it$?$

$1.$ The predicate P $.$x; y$/$ D $$y x D $1$ where the domain of discourse is Q$.$

$2.$ The predicate P $.$x; y$/$ D $$y $<$ x$$ where the domain of discourse is R$.$

$3.$ The predicate P $.$x; y$/$ D $$y x D $2$ where the domain of discourse is R

without $0.$

$4.$ The predicate P $.$x; y$/$ D $$yxy D x$$ where the domain of discourse is the

set of all binary strings, including the empty string.