The three types of persuasive strategies are logos, ethos and pathos, or L.E.P. The most effective persuasive communication usually has a mix of all three strategies. Logos uses logic or reason to reach a conclusion, while ethos depends upon the credibility of the author or source as support for action.
The answer is B because The context clue you would use if you did not know the meaning of the word atrocious is the fact that The D.A.R. was unsupportive of African American performers. One can assume that if the group is unsupportive that they would have made the experience extremely difficult for Marian Anderson.
They most likely wanted slaves to be afraid so they did not collect the courage to escape or disobey. With low self esteem they might not try anything.