I'd say the fourth option is the answer. It sounds the most sensible.
(I'm sorry if I'm wrong)
Answer:
I'd say the answer is someone who saw the event happened.
Explanation:
I don't know too much about arts but I'd say firsthand would be someone who saw it, the other answer choices do not make sense either. Sorry if this answer and/or explanation did not help.
Answer:
What are the options?
Explanation:
Message me the options and I'll help.