A PARENT $-$in$-$law is the parent of one's spouse. Choose the correct Prolog rule

$.$ parent$-$in$-$law $($X$,$Y$)$:$$parent$($X$,$ U$)),$ parent $($Y$,$V$).$ Married$($ U$,$ V$)$

parent$-$in$-$law $($X$,$Y$)$:$$married $($Y$,$Z$),$ parent $($X$,$Z$).$

$.$parent$-$in$-$law $($X$,$Y$)$:$$married $($Y$,$ U$),$ married $($V$,$Y$),$ U$=$V

parent$-$in$-$law $($X$,$Y$)$:married $($Y$,$W$).$child $($X$,$W$)$

$,$parent$-$in$-$law $($X$,$Y$)$: child $($Y$,$W$),$ parent$($X$,$Z$),$ W $\backslash =$ Z