The correct answer is A) Mark Twain.
All of the following individuals were famous American writers from the first part of the 19th century EXCEPT Mark Twain.
Mark Twain (1835-1910) was an American, one of the most important literature exponents in the second part of the 19th century. He wrote famous books such as "The Adventures of Tom Sawyer," "The Adventures of Hicle Berty Finn," and "The Gilded Age."
The ones who were famous American writers from the first part of the 19th century were Ralph Waldo Emerson, Ida B. Wells, Edgar Allan Poe, Walt Whitman, Washington Irving, Harriet Beecher Stowe, and Henry David Thoreau.