I’m from the U.S., not Canada, and that question is a little weirdly phrased. I would interpret it as “What classes are you taking?” in which case “taking” means enrolled in (a class). It could also be interpreted as “What major are you in,” but in U.S. English, that would more commonly be phrased as “What are you studying?” My recommendation is to ask what the person means by their question! Then you’ll know for certain

Hi! Native English speaker here. First of all, to use “arrive” you need to include the word “at” - 1) Hi John, I have arrived at the place. 2) Hi John, I have reached the place. Besides that point, both work in your sentence, they just sound a little formal. I usually use arrive/reach for objects: 1) The package arrived at my house last night. 2) The car reached Las Vegas yesterday. That said, “reached” is less formal and more appropriate than arrived for the way you are using it. I would more likely say: 1) Hi John, I’m at the place. or (less commonly because it is longer) 2) Hi John, I got to the place. Hope this helps!