Which of the following sets of events is in the correct chronological order?
 A. Missouri Compromise, "popular sovereignty", Dred Scott decision handed down
 B. Kansas-Nebraska Act (Nebraska doctrine), Missouri Compromise, President Franklin Pierce finishes term
 C. Silliman letter, Dred Scott decision handed down, Kansas-Nebraska Act (Nebraska doctrine)
 D. Lincoln delivers "The House Divided" speech, Lincoln elected U.S. senator, Lincoln elected president