Respuesta :
Okay so I'm not sure exactly if this is talking about primary or secondary sources, but if it is then I'm fairly certain that this would be a secondary source since the student wasn't there to witness it, they're relying on their research to give them information.
The correct answer would be Reliable. Research papers, Textbooks, Dictionaries, Encyclopedias, etc. are all Reliable Sources.
Hope This Helps :)