My suggestion will be don't invest all in just 1 altcoin it is not a really good idea. Do your own research and try to find out the project which has use-case and actively developing. Coin with a low-market cap is the best to get huge returns in a short period of time, not all the low-caps are good but you can find out some of the best by looking into their roadmap and dev team.
Agree! Should do his own research and assessment. Do not trust someone else's opinion because most of them have vested interest on what they are suggesting. And yes, should diversify your portfolio, even if your money is not that much, you can still distribute it to lessen the risk of losing all your money.