When did ottomans lose territory in crimea?

Crimea was a Turkic state part of the Ottoman Empire from 1478 until 1774 when the area became an independent state as a consequence of the treaty created by the Ottomans and the Russians. Later on, in 1783 Crimea was annexed to the Russian Empire.

The Crimea area was important for the Ottoman Empire as the Ottomans would usually go to the area for slave trade. The Crimeans mounted raids against different towns that were near by, from Poland, Russia or Lithuania. They would enslave people that they would capture during these raids, and later on sell them to the Ottomans who used the slaves for battles or different activities their communities needed.

c. the dred scott v. sandford case,

i think the answer is a and i hope this ; ))