Bitcoin for sure. I dont consider any of the other cryptocurrencies much of a contender in this regard. Bitcoin goes up even though some might think its not going to... They thought the same at 10k and 15k...
It's really weird when you say "They think the same at 10k and 15k ..." so I want to ask what makes them think that and what's the same for thinking? Since Bitcoin is far from that figure at this point, I hope you are not sleeping at the moment. 