Between those three, I would choose Ripple. Ripple already has a lot of partnership with financial institutions for private blockchain implementation. Their names are already out there, so it's good to assume a decent growth will come in the coming years.

But my personal choices for long-term hold are Litecoin and Ethereum. Litecoin has a new opportunity now as Bitcoin fees are rising. I hope to see more major merchant, like Steam who recently took off Bitcoin from their payment methods, accepting Litecoin as an alternative to Bitcoin. 2018 would be so good. For Ethereum, right now their network is being raped by kitties so that's a good point to entry. Ethereum will always be that advanced altcoin with so many potentials. Let's just hope that Vitalik&co could resolve the current issue with kitties