Answer:
The sentence "Everybody's doing it" applies to the bandwagon persuasion tactic.
Step-by-step explanation:
When someone refers to the bandwagon, it usually means that someone is saying everyone is on the same team about a topic. In advertising, the bandwagon tactic is often used to convince viewers that their product is truly the best and you should buy it since everyone else in society is. This also is what we call a 'fear-of-loss' tactic.
Example: "Come join the party! There will be drinks and music; not to mention 'everyone' will be there. You have to come!"