The correct answer is: Painfully extracting.
The oxford dictionary has some definitions that are close to the one used in this sentence. "Obtain something with difficulty or efford" and "cause pain or distress to".
This sentence belongs to Abraham Lincoln's "Second Inaugural Adress", here he addresses the slave owners, the things that they obtain are product of the effort of the slaves, by way of pain and suffering. The owners are rich and can have luxuries because they exploit the slaves, not because of their own work.
