Which of the following is NOT a superkey in a relational schema with attributes $V, W, X, Y, Z$ and primary key $V Y$?

A superkey is any superset of a candidate key (or primary key).

Here, the primary key is $VY = \{V, Y\}$. Therefore, any set of attributes containing both $V$ and $Y$ is a valid superkey:

• Option A: $\{V, X, Y, Z\}$ contains both $V$ and $Y$, so it is a superkey.

• Option B: $\{V, W, X, Z\}$ does not contain attribute $Y$, so it cannot be a superkey.

• Option C: $\{V, W, X, Y\}$ contains both $V$ and $Y$, so it is a superkey.

• Option D: $\{V, W, X, Y, Z\}$ contains both $V$ and $Y$, so it is a superkey.

Thus, option B is NOT a superkey.