The controversy over missouri's request for statehood: did not affect the balance of power in congress was settled by the missouri compromise precipitated the webster "liberty and union" speech all of the above

First off, the controversy of this had led to an imbalance in congress among the number of free states and slave states. So this rules out our first option. Due to it not being all of the above, that's our fourth answer ruled out as well. The Webster speech did not happen for 10 more years so it is very unlikely that this is what led to that speech. Even without the process of elimination, it would be B because the Missouri Compromise admitted Missouri as a slave state and Maine as a free state in order to preserve the balance of power in congress. Also, Henry Clay (the Great Compromiser) drafted this.