$x+y$ $\Rightarrow$ $x \ OR \ y$
$xy$ $\Rightarrow$ $x \ AND \ y$
$x + y + z = 1$
$xy = 0$
$xz + w = 1$
$xy + z'w' = 0$
$xy = 0$ $\rightarrow$ $xy = { \{01,10,00\} }$
$option \ C$ is eliminated $\because$ $x = 1$ , $y = 1 \ and \ x.y = 1 \ but \ we \ need \ 0 $
$xy + z'w' = 0$
$0 + z'w' = 0$ $\because$ $ xy = 0 $
$ z'w' = 0$ $\rightarrow$ $zw = { \{01,10,11\} }$
$option \ B$ is eliminated $\because$ $z = 0 , w = 0 \ \ \ \ \ \ \ z' = 1 , w' = 1 \ \ \ \ \ So , z'w' = 1.1 = 1 \neq 0 $
$option \ A$
$x = 1, y = 0 , z = 1, w = 1$
$1.$ $x + y + z = 1$ $\Rightarrow$ $1 + 0 + 1 = 1$
$2.$ $x.y = 0$ $\Rightarrow$ $1.0 = 0$
$3.$ $xz + w = 1$ $\Rightarrow$ $1.1 + 1 = 1$
$4.$ $xy + z'w' = 0$ $\Rightarrow$ $1.0 + 0.0 = 0$
$option \ D$
$x = 0, y = 1, z = 1, w = 0$
$1.$ $x + y + z = 1$ $\Rightarrow$ $0 + 1 + 1 = 1$
$2.$ $xy = 0$ $\Rightarrow$ $0.1 = 0$
$3.$ $xz + w = 1$ $\Rightarrow$ $0.1 + 0 \neq 1$
$option \ A $ is correct