Answer :
In the context of nineteenth-century American poets, Margaret Fuller was not a poet; she was a prominent American journalist, critic, and women's rights advocate. Here is a breakdown to further clarify:
1. Emily Dickinson: Known for her unique style and introspective poems, Emily Dickinson was a renowned nineteenth-century American poet who explored themes of death, nature, and existence.
2. John Greenleaf Whittier: Another notable poet of the nineteenth century, Whittier was known for his poems focusing on social issues such as abolitionism and nature.
3. Henry Wadsworth Longfellow: Longfellow was a celebrated poet whose works, including "Paul Revere's Ride" and "The Song of Hiawatha," made him one of the most popular poets of his time.
4. Margaret Fuller: While Margaret Fuller was a significant figure in nineteenth-century American literature and advocacy, she was not a poet. Fuller was known for her influential writings on women's rights, transcendentalism, and literary criticism.
Therefore, among the options provided, Margaret Fuller stands out as the individual who was not a nineteenth-century American poet.