Bitcoin.

But if i have additional money maybe like $200 i can split such into 2 or 4 and make an investment on other reputable alts i know i can afford taking risk on, but the only Investment that will not rise a blood pressure is bitcoin, but when we are experienced enough, we may also choose to make an addition of other cryptocurrencies we have researched about and hodl at our own risk, they may work out or not.