I’d probably vote A or D. Personally, I back up my local files and configs to a local NAS (2 x 4TB) and to an encrypted GDrive. No storage cap on the GDrive, but I’ll periodically (once every month or two) go through and delete any old/duplicate backups that I don’t need any longer to not abuse the storage too much.
But… there’s more than one way to skin a cat and I’m sure everyone here has their own method to their madness, so you’ll probably just want to figure out what works best for you. I like having a copy of everything locally (hence why I use a NAS), but you’ll be paying more up front for the initial investment of the hardware. Remote storage boxes are nice if you don’t mind the traffic, but that bill does add up over time and just be mindful that providers such as Kimsufi/Online are probably using old drives/hardware that could fail at any point in time. Block storage with some such as Fran/BuyVM comes out pretty cheap too ($1.25/250gb/mo iirc) and you can scale as needed and buy more storage, so that’s an option as well. LetBox usually run some nice block storage specials as well (something like $7/mo for 3TB, maybe be on the lookout for black friday sales next week).
There’s been some other threads on this subject, so you might get some ideas by perusing them: