A. the effects of violence. I believe this is correct. The speech I am reading is a Ceremony for the War Dead , it mentions the effects of war a lot.
B. the difficulty of change. Although he mentions change, the theme is no the difficulty of change, maybe the necessity.
C. the quest for knowledge. In his speech there is no mention of the quest for knowledge.
D. the struggle for meaning. I do not see anything that mentions a struggle for meaning.
As you can see from above, the answer should be A.
Have a great day! :)