单项选择题

Questions 14 to 16 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. When did the greatest numbers of immigrants reach the United States of America

A.From 1840 to 1880.
B.From 1880 to 1914.
C.From 1818 to 1914.
D.From 1820 to 1890.