托福【模拟测试-5】-2017服务一体化 Why does the professor discuss a letter written by Benjamin Franklin?

A. To demonstrate that some did not approve of using the bald eagle as the national emblem

B. To give details about the process of selecting a national emblem and creating the Great Seal

C. To argue that the bald eagle has been the national emblem since the country's founding

D. To answer the student's question about why a bird was selected as the national emblem