How does the reader know that “The Tell-Tale Heart” is not a poem?

A. The setting is at night.
B. It is written in first person.
C. It contains a male protagonist.
D. It is not written in stanzas.

D. It is not written in stanzas.

To determine that "The Tell-Tale Heart" is not a poem, one can look for certain characteristics that are typically associated with poetry. Here is an explanation of why each answer choice is correct or incorrect:

A. The setting is at night: This answer choice is unrelated to determining whether the text is a poem or not. The setting of a story does not dictate its form.

B. It is written in first person: This answer choice is correct. Poetry can be written in various perspectives, including first person. The fact that "The Tell-Tale Heart" is written in first person does not indicate it is not a poem.

C. It contains a male protagonist: This answer choice is also unrelated to determining whether the text is a poem or not. The gender of the protagonist does not dictate the text's form.

D. It is not written in stanzas: This answer choice is correct. Stanzas are a common structural element found in poetry. Since "The Tell-Tale Heart" is not written in stanzas, it suggests that it is not a poem and, therefore, this is the correct answer.

Therefore, the correct answer is D. It is not written in stanzas.

The reader can know that "The Tell-Tale Heart" is not a poem because it is not written in stanzas. This is option D.