Personally I stick it all in US index funds and am averaging more than 20%/year over the last five years (although I'm not supposed to look at it).

Seems quite bond heavy though. If you have a choice, 60/40 stocks/bonds (preferably global, equal-weighted vs cap weighted for the stocks to take advantage of the higher growth of small and mid caps).

Let me say something about Option B: Being a landlord is not passive. There are many young people here, some who have made some good money, that buy and rent property. If they describe it as easy it's because they likely haven't owned the property long enough to have to pay for big maintenance projects, or long enough to have had bad tenants.

Investments are an efficient machine, and they don't produce easy money. The long-term real returns on real estate are steady and low. TINSTAAFL. Any advantages come from being able to leverage a down payment with a mortgage, which may or may not be possible for a rental property.

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')

For Citizens in the EU.

While keeping a low risk, what are good options to maximize ROI for a ~5yr investment? (local bank conservative investment funds have a history of 2% for previous 3 years)

Thanks

Ideally buy a triplex or a fourplex and live in one of the units.

Depending on your location... you may be able to break even with 3 units rented and therefore allowing you to live free for the rest of your life.

If you are looking for risk aversion ...

Most solar companies offer abysmal returns. Major US companies have gone bust. Well run companies can blow up if the government changes policy on subsidies. In Ontario - the government just decided they would stop paying 82 cents/kw/h for solar, and dropped it to 50 cents/kw/h. Imagine what that would do to your balance sheet.

You can make possibly better returns, but it's not remotely 'low risk'.

Getting out of the 3% ROI range is quite hard while not getting into extra risk.

There are currency hedged funds if that's an issue for you.

Disclaimer: I work there