If you want the least amount of risk with potentially 20% gain, I'd go with bitcoins. or maybe some Ripples
Investing that dollars in bitcoin is much better and not 20% but he will earn a large amount of profit if he do not spend them early and hold them for longer time at least for 1 year.
I think the bitcoin is a good investment for the long time. That has been proved in the past 6 years.
i think is not is bitcoin investmentment to long time , buy and hold bitcoin over one year is not good
if you want maximum profit must in day trade in use pair altcoin
One year is not considered as long term investment for me, my long term investment falls for the range from 5 years up.. If you sell within one year you can only expect and 100% or less growth of your investment, my computation is based on the current year growth.
Holding bitcoins for next 5 years can be risky as we don't know what future holds for us as price can even go down or may be bitcoin can disappear, so the smart move will be to sell them when you are making enough profits from it and buy them back when you see downfall in the price.