Find all the free variables this wff $($that is$,$ free occurrences of a variable$)$:

ExEyL$($x$,$y$)$&Ez$($B$($x$,$y$,$z$)$&AuB$($w$,$z$,$u$))$

Select ALL the variables below if there is any free occurrence of it in the wff$.$

Group of answer choices

w

y

x

u

z