If your speech has a lot of adjectives, it is possible that your text is not very optimized when it comes to explaining something. If you want an example on how that might be the case: until now, there is only one adjective in use in this text that you are reading: optimized. Your speech can have many adjectives in a single sentence, though.
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.