head scratcher!!?

[poorboy_9]

I'm correcting my student's essays and have run into a snag!
Which is "more correct":
I'm an NBA player -or- I'm a NBA player
I know the a/an vowel rules, but the linguistic flow seemes to favor "an";
"it just sounds better". (I know, I know...thats no reason to do it!)
If there is anyone who may know an obscure rule, or reason (other than it "sounds" better) I would be forever in your debt....
B.

[David L.]

If you pronounce/sound-out NBA it becomes, En-Be-A

Since NBA begins with a vowel sound, we use 'an'. The first letter doesn't actually have to be a vowel!

[poorboy_9]

David L.,
Many thanks!!! ...just like "an hour".
Thanks, I was perplexed. n' positively puzzled.
B.