Select the Boolean expression that is not satisfiable.

$(z+u)(z+x)(z+x^{-})(u+y)(u+y^{\text{'}\text{'}})$

$(z+u^{-})(z+x)(z+x^{-\text{'}})(u+y)(u+y^{-\text{'}})$

$(z^{-}+u)(z+x)(z+x^{-})(u+y)(u+y^{-})$

$(z^{-}+u^{-})(z+x)(z+x^{-})(u+y)(u+y^{-})$