A. Charlie's friends could potentially be a helpful influence when it comes to binge drinking. They could motivate Charlie to avoid this practice. They could also remind him of the dangers of binge drinking. Finally, they could also suggest going somewhere else where this is not happening.
B. Charlie's friends could also prove to be very unhelpful. They might pressure Charlie into participating. They might also make fun of him or mock him if he decides to abstain. Finally, Charlie's friends could potentially set a bad example that Charlie might follow.