The correct answer is D. Mark Twain.
Mark Twain was an American author and humorist. He is best known for his novels The Adventures of Tom Sawyer (1876) and Adventures of Huckleberry Finn (1884), the latter often called “the Great American Novel”.
John Ruskin was an English art critic, social thinker, and philanthropist. He is considered one of the most influential critics of the Victorian era.
William Shakespeare was an English poet, playwright, and actor, widely regarded as the greatest writer in the English language and the world’s greatest dramatist.
Leo Tolstoy was a Russian writer who primarily wrote novels and short stories. Tolstoy is widely considered one of the world’s greatest novelists.