Consider the quotation from Thomas Jefferson:

"[The question of slavery], like a fire bell in the night, awakened and filled me with terror. I considered it at once as the [death] knell of the union." —Thomas Jefferson, 1820

In this excerpt, Thomas Jefferson expresses profound concern about:

a) Waking up at night
b) The sound of a fire alarm
c) The debate over slavery
d) All of the above