Here is my answer, I typed it in a document because I didn't want to have a long answer here, picture below. I hope I helped! :-)
Answer: The journal of someone who was there at the time.
Explanation: The journal of a person who was present at the fall of the Berlin wall would be a perfect source, or footage of the event, or anything first-person. People who were actually there and participated are always the best sources for any historical event. (:
Answer:
C I think I'm so so sorry if I get it wrong