Many people spoke out against slavery in response to
a. the admission of california to the union as a free state.
b. the establishment of the underground railroad.
c. the passage of the fugitive slave act.
d. the practice of popular sovereignty.

Many people spor out against slavery in response to the passage of the fugitive Slave Act.

Explanation:

The Fugitive Slave act was a law passed by the congress that stated that all fugitive slaves had to be returned to their masters and that free citizens or states had to cooperate to do that. It was a result of the Mexican-American war end that brought new territory to the U.S. and had to be aligned to the Nation's rules. It was a really big impact in society because those new states didn't' really were accustomed to slavery and were being integrated to a new system they had to accept thanks to their inclusion to the US. One of the major factors was the nullification of it.

the correct answer is ligma : ) jk but i think its c