Can you give specific examples from the story to support your answer?
I agree with #4 and here is why: There is a lesson learned and the main character experience a transformation or a change of thought, albeit at a minor scale. Yet, this change occurs as a result of something that happens that is not enjoyable nor exciting. In fact, it is pretty sad. So, for the likes of a teenager to experience something like that, the chances are that the experience is of a big magnitude. I am sure this is one of those experiences that Sammy may recall in the future with a bit of embarrassment.
Can we call it a tragic-comedy, which often is what adolescence is? Since Sammy possesses a false pride and sense of grandeur beyond his scope, he certainly sets himself up for a fall; then, like Oedipus Rex he learns humility. But, the tragic elements end there. The rest of the narrative is a bit tongue-in-cheeck as the reader watches the histrionics of adolescents who perceive themselves--rather comically--as adults.
In strict terms, the story of Sammy does not end happily for him. The girls that he was so staunchly defending end up ignoring his noble gesture, he quits his job, and says that he knows life will be harder for him after that. Therefore, the story would be considered a tragedy. However, if you look beyond what Sammy wants and look at his experience as a moment in maturing, then the story might change to a comedy. It certainly has comedic moments, such as Sammy's description of "Queenie" and the girls as "bees" fluttering around their queen. To one who has experienced the ups and downs of growing up, his reaction to the store manager can also be seen, not as a tragedy, but as an experience that will teach Sammy the realities of life. In the end, Sammy will certainly be less naive and more realistic in his future decisions. So, in that case, the story is more comedic because it seems the protagonist actually will eventually overcome his anger and learn from the experience. He gives a hint of that when he says, "Life will be harder". Yes, life indeed will be harder because adults see many sides of an issue, something Sammy did not see. But the inference is there that he will see the more difficult sides of issues in the future.
The story does not fall into either category. A tragedy involves the death of the main character and most of the principle characters, that does not happen here. I would say that A & P is a cautionary tale, with a moral, or truth about life expressed at the end.
Clearly, Sammy's decision to object so strongly to the girls being yelled at for failing to obey the rules about wearing clothing in the store provides him with an opportunity to exercise teenage rebellion. For a brief moment, he feels on top of the world, until the reality of his choice sets in and he realizes that he really needed his job.
The story also illustrates cause and effect. Risk vs. return, Sammy risks everything for a possible return, attention from the girls. He loses big.
The girls, and who'd blame them, are in a hurry to get out, so I say "I quit" to Lengel quick enough for them to hear, hoping they'll stop and watch me, their unsuspected hero. They keep right on going, into the electric eye; the door flies open and they flicker across the lot to their car, Queenie and Plaid and Big Tall Goony-Goony (not that as raw material she was so bad), leaving me with Lengel and a kink in his eyebrow." (Updike)