Questions 18 to 20 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions. Now listen to the passage.

Why does the speaker mention Mark Twain

A．To give an example of someone who was the subject of one of Stowe’s biographies.
B．To give an example of anther author who used local dialect in his writing.
C．To suggest that his work was less popular than Stowe’s.
D．To point out another author who wrote about New England.