<span>Louis, Dauphin of France (1729–1765) </span>
The idea that reconstruction ended discrimination is a gross fallacy. After reconstruction ended, lynch mobs still existed, the KKK ran rampant, poll taxes, literacy test, and other restrictive measures stopped them from gaining any political clout, socially they were still viewed as inferior by many people, and economically they were unable to gain advantageous positions and become monetarily comfortable enough to gain a middle-class identity.
The answer that best describes the rhetorical strategy that Henry uses here is D. rhetorical question. Rhetorical questions are those that do not necessarily demand an answer - the answer is either obvious so it doesn't have to be stated, or there is no reason to say it.
However, if you need more than one option, I'd also choose interrogative statement, given that this strategy involves the use of questions, which fall under the category of interrogative sentences.