Concept:Build a vertical order from the given "above/below" relations and find the lowest book.
Explanation:Book X lies above W: X is higher than W.
W is above Z: W is higher than Z.
V is below Z: Z is higher than V.
Y is below V: V is higher than Y.
Combining these relations, the order from top to bottom is:
X → W → Z → V → Y
Therefore, Y is at the bottom of the stack.
Answer:Option B — Y
