A firsthand account of an event is told by-- someone who did not see the event
someone who has a strong opinion about the event
someone who saw the event happen
someone who does not have all of the knowledge about an event

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.

Someone who saw an event happen

Explanation:

Firsthand knowledge of an event is knowledge based on direct experience or observation.