Select the Boolean expression that is not satisfiable.

The following multiple$-$choice options contain math elements, so you may need to read them in your screen reader's $$reading$$ or $$browse$$ mode instead of $$forms$$ or $$focus$$ mode.

Choice $1$ of $4$:

y

$$

$($

u

$$

$+$

y

$)$

$($

z

$+$

x

$)$

$($

z

$+$

x

$$

$)$

$($

z

$+$

u

$)$

y

$$

$$

$($

u

$$

$+$y$)($z$+$x$)($z$+$

x

$$

$)($z$+$u$)$

Choice $2$ of $4$:

y

$$

$($

u

$$

$+$

y

$)$

$($

z

$+$

x

$)$

$($

z

$+$

x

$$

$)$

$($

z

$+$

u

$$

$)$

y

$$

$$

$($

u

$$

$+$y$)($z$+$x$)($z$+$

x

$$

$)($z$+$

u

$$

$)$

Choice $3$ of $4$:

y

$$

$($

u

$$

$+$

y

$)$

$($

z

$+$

x

$)$

$($

z

$+$

x

$$

$)$

$($

z

$$

$+$

u

$)$

y

$$

$$

$($

u

$$

$+$y$)($z$+$x$)($z$+$

x

$$

$)($

z

$$

$+$u$)$

Choice $4$ of $4$:

y

$$

$($

u

$$

$+$

y

$)$

$($

z

$+$

x

$)$

$($

z

$+$

x

$$

$)$

$($

z

$$

$+$

u

$$

$)$

y

$$

$$

$($

u

$$

$+$y$)($z$+$x$)($z$+$

x

$$

$)($

z

$$

$+$

u

$$

$)$