The correct answer is: "the Great Compromiser.”
Henry Clay (1777-1852) was known as The Great Compromiser due to his crucial participation in the issuing of the Missouri Compromise in 1820, that ended a sectional crisis over slavery.
The Missouri Compromise established the incorporation of the state of Missouri to the United States as a slave state, and the simulatenous admission of Maine as a free state, which would keep the balance of power between slave and free states, in other words, between Southern and Northern states in the US.