Final answer:
The two excerpts highlight the hardships faced by civil rights activists, pointing to the conclusion that the movement was difficult and trying for many participants.
Step-by-step explanation:
Based on the excerpts from both "I Have a Dream" and "Letter from Birmingham Jail," the reader can infer that D. The civil rights movement was difficult and trying for many. The excerpts detail the struggles faced by civil rights activists, mentioning trials and tribulations, police brutality, and the need for self purification and preparation for ordeals of jail. They reveal the depth of the challenges encountered, including discrimination, violence, and the need for moral courage to withstand these hardships without resorting to violence in return.