Step 1: Understanding the Question:
We have to check which pronoun is correct after the linking verb "are" in "Those are them" and "Those are they."
Step 2: Key Formula or Approach:
A linking verb such as is, are, was, or were does not act on an object. It simply joins the subject to a word that renames or describes it, called the subject complement. Since a subject complement points back to the subject, it must be in the subjective case (I, he, she, we, they), not the objective case (me, him, her, us, them).
Step 3: Detailed Explanation:
In sentence 1, "Those are them," the word "them" is objective. We use the objective case for the object of a verb or preposition, as in "I called them" or "give it to them." Here "them" is not receiving any action, it is renaming "those," so the objective form is wrong.
In sentence 2, "Those are they," the word "they" is subjective, and it correctly renames the subject "those" after the linking verb "are." This is the same pattern seen in formal expressions like "It is I" and "This is she."
So sentence 1 breaks the subject complement rule, while sentence 2 follows it correctly.
Step 4: Final Answer:
Option B fails because the second sentence is not wrong, it is grammatically sound. Option C fails because only one of the two sentences is wrong, not both. Option D fails because sentence 1 clearly breaks the rule. Only the first sentence has an error.
\[ \boxed{\text{Option A: The first sentence has an error}} \]