To determine which electromagnet will produce the strongest magnetic force, we would typically need additional information such as the number of turns of wire, the current flowing through the wire, the core material used, and the design of each electromagnet (e.g., the size and shape).
Without this specific data regarding electromagnets W, X, Y, and Z, it's not possible to definitively identify which one produces the strongest magnetic force.
If you have more details on the electromagnets, please provide that information so I can help you assess which one is likely the strongest.