سوال ۱ کنکور ارشد فیزیک ۱۴۰۵

The sentence needs a noun that means the place/origin from which information is obtained. The fixed collocation is "a source of information." Instagram is not a good source of medical and health-related information. "Discovery" (something found), "cause" (what produces an effect), and "agreement" (mutual understanding) do not collocate with "of ... information" in this meaning.