The admission of missouri as a slave state was controversial in the senate because a. the senate was proslavery. c. it would upset the balance. b. it would create sectionalism. d. the senate was antislavery.

c. it would upset the balance

Explanation:

The idea of the federation and the Union of the States was to eventually abolishing slavery, all of the efforts were to bring the pro-slavery states to an agreement unti abolishing slavery, and the forces between pro-against slavery states was fairly balanced, adding Missouri to the Union would mean that the senate approved the anexation of slavery states and miss-balancing the pro vs against slavery states.

answer; /// slavery should be outlawed in the new country, was part of the initial draft of the declaration of independence, but not part of the final