As a Am-eng native speaker, I think duo needs to accept "this is the original" as an appropriate translation for this sentence, as it is for more likely to be said than "here is the original".
"This is the original." would be "Das ist das Original." or "Dies ist das Original."
Die da drüben ist eine Kopie. Hier ist das Original. - The one over there is a copy. Here is the original
I agree with you, cuKSL.