Answer:
b.the admission of California might permanently tip the political balance against them.
Step-by-step explanation:
The admission of California as a free state was an issue that ignited controversy along sectional lines. Southern representatives did not want more legal provisions or solutions that could limit the practice of slavery, presidents had to work out a delicate balance. The Wilmot Proposal to ban slavery in the territory that the US would win in the Mexican-American War was not approved, but it deepened divisions. The issue of slavery divided American politics since the 1820s until the outbreak of the Civil War in 1861.