The part s showing troop movement
Many nations wanted to find the U.S passage, because they wanted to find a quicker route to Asia. They thought going around Africa was way too long and going across the Mediterranean Sea was too expensive and risky. They thought that sailing west would get them to Asia in no time. In reality, it was North America and they would have to go much farther in order to get to Asia, but they did not know that back then.
The 3/5 Compromise is also known as the federal ratio.
It established the ratio by which a slave would count as 3/5 of a free man for the purposes of establishing population, which was instrumental in setting the amount of house seats.
I think it’s C because enslaved ppl are a primary source of information so they would be reliable.