Define 'best'. What are your goals? For example, if you want to maximize expected ROI over decades, the answer will be different from the one when you want to maximize worst-case ROI over a year.
Also, "For USA citizens" isn't disjunct from "For those living in Europe", and "Europe" is quite diverse (even if one reads it as 'in the EU', tax laws may affect what's 'best')
Also, avoiding the euro may, depending on what you want to do with the funds, add exchange rate risks, with their pros and cons (higher variability of ROI). If you want to spend the money in what now is an euro country, I don't think there is a way to take exchange rate risks (either because of investing in other currencies or because of not knowing a possible euro exchange rate)
And I think option B should be disqualified as it doesn't meet your requirement of 'passive' (you know that, based on the remark 'too much hassle')