An activity or a service performed by volunteers free of charge of a person, group, or the public is called

from the word list given, the most suitable words that relate to the reason information were written would be:  

objectivity: lack of bias, judgment, or prejudice

accuracy: free of mistakes, to be correct

authority: the ability to tell people what to do or believe in

content: to be satisfied  

it can be said that the author made the article to present objectivity, to provide accurate information, to be the authority in the subject that he or she writes, and to be satisfied of the information quality given out.