Final answer:
The direct cause of sectionalism that should be categorized is The Missouri Compromise, as it dealt directly with the admittance of free and slave states and maintaining a balance of power. The correct answer is option: 1) The Missouri Compromise.
Step-by-step explanation:
The direct cause of sectionalism that should be categorized is The Missouri Compromise. This key event highlighted the sectional differences between the North and South by establishing a precedent for the future admission of states and the balance of power in Congress.
The Missouri Compromise was a response to the tension caused by the request for Missouri's admission as a slave state in 1820, which threatened to upset the balance between slave and free states in the Union.
To maintain the balance, Maine was admitted as a free state and Missouri as a slave state. Additionally, the compromise drew a line across the Louisiana Territory, establishing a boundary between future free and slave states.