Check your undergraduate transcript - you may have taken it already, but the class title might have been different. Look up the course curriculum and overview, print it out, and submit a request for credit evaluation. You might get it approved without taking anything. (I had this happen with a psychology class - the community college gave it a sexy title to attract students, but the curriculum matched my undergrad school's psych course with a more traditional title. Had to submit the documentation to get the credit - saved me $900!)
Since you're in a master's program, it's possible that your current school is disallowing undergrad coursework because the credits are too old. There's typically a five-year limit on getting credit for undergrad work, which I think is absurd. I entered grad school six months too late and was only credited for my UG major.
I had a similar "one class missing" situation with Accounting - I had 15 credits in undergrad acctg courses from the university, but their own grad school wouldn't recognize them because they were six months too old. I tried studying and taking the evaluation test, but I didn't pass it because the course was cost accounting, but the test included managerial accounting topics that I hadn't studied.
I was ticked off and not willing to pay $400/credit for coursework at the university. I met with an advisor from a local community college and they let me take the course during intercession as a non-matriculated student. Before I enrolled, I had my grad school advisor approve the course, to ensure that I could transfer the course and fulfill the requirement.
It was a 2 day/week, four-week course and I breezed through it with an "A," but it transferred as a pass/fail, which was fine.
Online courses are convenient, but you might have to take an actual class. I don't think NC State or UNC are your best bets - you have to look at local community colleges like Alamance and NCCU. The college needs to be accreditated, but it doesn't have to be a four-year school, so look at the two-year schools and voc-tech schools. Their schedules are better for part-time students than NC State, which really focuses on full-timers.
I called one CC and they are charging $426 for a lit class. Checked into CLEP and the sample questions are very hard. Can't imagine passing that. But that would be a great option if I could remember that far back.
