Learning from things should always be a good thing, even if it comes from something bad. Finding people with common interests can be good as well. The answer is C because if you accidentally post something bad, it could stay on the internet forever, and possibly hurt your chances to getting some job someday.
Explanation: Learning from others is great, so is finding people with similar interests, but having permanent posts that leave a trail isn't. After you post something online, it's always there, regardless of wether you take it down or not. This can be very detrimental to people if not cautious.
