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

Ax$($R$($x$,$y$)->$EyAz$($L$($y$)$&L$($w$)$&R$($x$,$z$)))$

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

Group of answer choices

w

y

u

x

z