Answer:
The United States as a whole.
Explanation:
In his speech titled "A House Divided", Republican candidate representative Abraham Lincoln talks about "a divided house" and how it could lead to disaster rather than success. This metaphorical speech is taken from the teachings of Jesus in the Gospels of Matthew, Mark, and Luke.
In the speech, he alludes to the nation of the United States as a house, a single umbrella entity. He also declares, "a house divided against itself cannot stand." Here, his reference to "a house" is the nation as a whole.
Thus, the correct answer is the fourth option.