Which of the following is categorized as a contemporary composer?

The correct answer identifies Poulenc as a contemporary composer. The term "contemporary" generally refers to composers who were active during the 20th century to present, an era that saw the emergence of diverse musical styles and techniques. Poulenc was part of the French group of composers known as "Les Six," and his work embraced a blend of classical traditions and modern influences, making him a significant figure in contemporary music.

In contrast, the other composers mentioned have strong ties to earlier musical periods or movements. Bartok, while active in the 20th century, is often categorized within the realm of early 20th-century modernism, which can be seen as a bridge between the late Romantic era and contemporary music. Copland is known for his contributions to American music in the mid-20th century and is considered part of the broader modernist movement. Beethoven, on the other hand, belongs to the Classical and early Romantic periods, primarily active in the late 18th and early 19th centuries, which places him well outside the contemporary classification. This context highlights why Poulenc is the best fit for the label of a contemporary composer.