Question

why was there great concern about admitting missouri as a slave state?
the louisiana purchase had required that there be no slave states within the territory.
there would be more slave states than free states.
it meant that maine could not have slaves.
transporting slaves to missouri was difficult.

Explanation:

Before Missouri's admission, the number of slave and free states was balanced. Admitting Missouri as a slave state would tip the balance in favor of slave states. This could give slave - holding interests more power in Congress (e.g., in the Senate where each state had equal representation). The Louisiana Purchase did not have such a no - slave - state requirement. Maine's status (it was admitted as a free state under the Missouri Compromise) and slave transportation difficulties were not the main concerns regarding Missouri's admission as a slave state.

Answer:

B. There would be more slave states than free states.