Six products – U, V, W, X, Y and Z – are to be placed in the display window of a vending machine with six compartments. Numbered 1 through 6 from left to right, the products must be placed in the window, one product in each compartment, according to the following conditions:

U cannot be immediately to the left or immediately to the right of V.
W must be immediately to the left of X.
Z cannot be in compartment 6.

Which of the following products CANNOT be placed in compartment 1?