Will mark BRAINLIEST and extra points

Why did Missouri's request to join the United States in 1820 cause a crisis?
O A. Adding Missouri would upset the balance between slave states
and free states.
B. Adding Missouri would prevent slavery from spreading in the
West.
c. Adding Missouri would increase the power of free states in
Congress.
O D. Adding Missouri would force northern states to accept the
Fugitive Slave Act.