I hope you don't mind such a late response to this, but I do have some observations. I can't offer you a hypothetical alternative mark unless I know what the assignment itself was; based on assumptions, B- seems reasonable. To be fair, I'm not a high school English teacher, so my second opinion is unlikely to do you any good.
That said:
1. You've got a decent start to developing a strong satirical style. A few things that I'd suggest working on if you want to go down that path:
- Keep in mind the audience you're writing for. As I'm fairly sure you know, keeping tone and style in mind are necessary to how your piece is received. The impression I got from your work seemed to indicate the assignment asked for a travel pitch of sorts. Did the assignment specifically call for cynicism, or did it expect you to take a more earnest approach? There's a time and a place, and I have no way of knowing if this was it.
- "Here in Alabama there are two gods: God Almighty, and Billy-Bob, the town's mechanic." This sentence has good flow to it, but, like a lot of your piece, it's based upon stereotypes and cliches. There's nothing wrong with that, inherently, especially in the style you've chosen! However, in order to add a necessary level of depth to it, there are methods you could use. Perhaps develop a narrator that genuinely believes the stereotypes you're portraying - it's easier to get people to laugh at bigots than at bigotry, and makes it clear you're writing in a character voice rather than your own. Or, in the case of short pieces like this, give contradictory facts. Either swear up and down that everyone in Alabama is a bible-thumping, tractor-driving, God-fearing redneck and give anecdotal evidence to suggest the opposite, or keep the details as they are while using sincere, flowery language to imply it's really a glamorous place.
- Similarly: Don't apologise! If you've done your job as a satirical writer, it should be self-evident that you don't personally believe everything you've written. I know it can be difficult, but it's necessary to separate yourself from your work. If it doesn't stand on its own, it doesn't stand.
If you don't want to pursue a satirical style in the future, clearly not all of this advice is useful for you. I'm offering you this criticism only because I think you could really make use of it. You have a good foundation for such a style - you simply haven't developed all the right tools yet.
2. Did you submit your work unedited? If not, why did you post it unedited on here? It's unreasonable to expect writers to catch every mistake - the longer one spends with one's own work, the easier it is to skim over flaws that seem clear to new eyes - but submitting unedited work as a final copy is never the best choice.
3. Make sure your voice is consistent, or that there are clear indicators of when and why it changes. Overall, you have a reasonable understanding of how words work - you have good sentence flow at times, variation in the length/structure of your sentences, and your word choice almost always suits the sardonically cynical tone of your work. That said, if you want to write in a 'hillbilly' voice: commit to it! If you waver in and out without indicators (eg. quotation marks, italics, some sort of formatting), it either comes across as lazy writing or simple grammatical error.
I know this is vastly unsolicited advice (and that you posted this nearly a month ago) but I wish you the best of luck!