Step-by-step Solution:

From statement (a) we know \( Z \subset Y \). From statement (b) we know the intersection of Y and X is empty (\( Y \cap X = \emptyset \)). Since all Zs are within Y, and Y completely excludes X, Z must also completely exclude X. This makes Conclusion II ("Zs are not Xs") TRUE. From statement (c) we know \( X \subset W \). While W contains X, there is no relationship defined that forces W to overlap with Z. W could exist entirely separately from Z. Therefore, Conclusion I ("Some Ws are Zs") is not necessarily true. Hence, only conclusion II follows.