Trading: Might less risky than those options that you've mentioned. You need to learn how the market works, stay updated with the cryptocurrencies news.
ICO : You need to do your own research, learn their whitepaper, find out who's behind that project, the team and their goals, some ICOs look promising but they failed. So you have to be careful.
Lending: Sorry, but I don't recommend this way, is too risky, people can run away with your money.
Bounty: It might be safe, but most of them are asking for verification or KYC, if you're concerned with the privacy you might not upload your identity.
I don't agree, crypto market trading is the hardest part of the mentioned choices. People fall to the traps of the unexpected market movements by market makers, crypto whales, scam project's team member, etc. The bounty projects and the lending are the "safest" if the OP knows what he/she is doing.