I'd say that the aspect of culture that this excerpt from "What For" by Garrett Hongo celebrates is A. holidays.
It is customary in some countries to spend holidays with family talking about past times, and reminiscing.
The answer should be B) because social media is a long distance communication tool for people, so not C) since that's false, that's where most danger is at is online, not D) because that wasn't the original purpose, but sadly its become popular now and not A) because that's incorrect.