Which of the following describes an acrostic?

An acrostic is a form of writing in which the first letter of each line, word, or paragraph, when read vertically, spells out a word or message. This device is often used in poetry to convey a hidden meaning or theme that aligns with the overall message of the poem. For instance, if the first letters of each line of a poem spell "LOVE," the work may explore themes related to love, creating an additional layer of meaning for the reader.

The other options describe different literary forms: a poem that tells a story in a structured format aligns with narrative poetry, a dramatic narrative featuring dialogue is characteristic of plays or certain types of scripts, and a type of free verse without patterns does not pertain specifically to an acrostic format, as acrostics involve specific structural features centered around the letters of words. This distinction helps clarify why the acrostic definition appropriately focuses on the arrangement and function of letters.