Which of the following works is attributed to Horace?

The correct answer is "Ars Poetica." This work is a crucial text in the study of poetry and literary theory, written by the Roman poet Horace around 19 BCE. In "Ars Poetica," Horace outlines his philosophy of poetry and addresses various aspects of the craft, including the importance of structure, style, and the emotional impact of poetry. It serves as a foundational treatise on the art of poetry and has influenced countless poets and writers throughout history.

The other options are well-known works by different authors. "Marriage à la Mode" is a series of paintings and illustrations created by William Hogarth, focusing on marriage and social issues in 18th-century England. "Dulce et decorum est pro patria mori" is a famous poem by Wilfred Owen that critiques the romanticism of war, particularly the experiences of soldiers in World War I. "First Fig" is a poem by Edna St. Vincent Millay that explores themes of love and desire. These works, while notable, do not relate to Horace and thus are not the correct answer for this question.