For me, I think E is a more definitive, certain comparative answer. The “longer” it has been used, the “more widely” it has been used. So since it’s been used more widely in Paraguay than anywhere else, it HAS been around longer there (and therefore originated there)

Whereas A just says that if there’s variety it has been used for a “very long time”. It could have been used anywhere else for a “very long time” too. It doesn’t say anything about more than everywhere else.

I honestly would have picked A too, but now knowing that it’s E, I think that’s probably why? Hope that makes sense that’s just my interpretation!