I'm starting to think the instrument is actually a piano
"Are you speaking of classical music in the sense of Mozart (for example) or things like classic rock? Apologies for the question but this category seems to be used for a whole number of purposes (e.g., also classic pop anthems etc) and I haven't figured out what the category actually is supposed to be for. If it's actual classical music, it might be Bach, Minuet in G Major (https://youtu.be/lNg9iMQDnIM?feature=shared). If not that, it might be Surf Curse "Freaks" (https://youtu.be/NfMegACVJQw?feature=shared)