$A)$ $\{X,W\}^+ =\{X,W,Y,U,Z\}$ ($V$ is not here)

$B)$ $\{U,V\}^+ =\{U,V,W,X,Z,Y\}$

$\{Y,V\}^+ = \{Y,V,U,X,Z,W\}$

$\{W,X,V\}^+ = \{W,X,V,Y,U,Z\}$

$C) \{X,V\}^+ =\{X,V\}$ ($U,W,Y,Z$ are not here)

Hence, $B$

$B)$ $\{U,V\}^+ =\{U,V,W,X,Z,Y\}$

$\{Y,V\}^+ = \{Y,V,U,X,Z,W\}$

$\{W,X,V\}^+ = \{W,X,V,Y,U,Z\}$

$C) \{X,V\}^+ =\{X,V\}$ ($U,W,Y,Z$ are not here)

Hence, $B$