“Which course are you enrolled in?” vs. “Under which course are you enrolled?”

If I want to ask someone about the course they are taking, what would be the more appropriate usage:

1. Which course are you enrolled in?
2. Under which course are you enrolled?

Solution 1:

I don't think the preposition under is commonly used to refer to being enrolled in a course. If you want to write the question without ending it with a preposition, you use the same preposition, but simply move it to the front:

In which course are you enrolled?

However, despite the exhortations of some grammar mavens, there's nothing wrong with ending a sentence in a preposition, and it's the more common way. So sentence #1 would be the preferred way.