While if you hadn't, you could either answer "Haven't got around to them yet" or, if there is a reason, "Sorry, I don't think I'll do X" and possibly add the because.

Framing!

I understand both why you can assume the worst and also that there's also a better interpretation - and that better interpretation is "I don't know if you've done art of (X), is there a positive reason for that?"
And then you can basically say "I have, it's here!" (The best answer!)