Which ones are the best investment, stock, cryptocurrency or NFTs?

Personally I believe that stock shares are better investment, simply because they are assets than can bring in future income and profits.

Cryptocurrency and NFTs do not generate stable income streams or stable profits. You can only make gains or loss by the time you sell them. However, due to the popularity of cryptocurrency and NFTs, I would say you can invest a very small part of your money to them. But I strong recommend that you do not put a large part of your money into the virtual assets.

Another reason is that, although some people preach cryptocurrency and NFTs to be scarce resources, they are actually not that scarce. There might be only limited amount of coins or paintings within their own systems, but if there can be, technically unlimited types of the systems. To be more specific, there are only limited amount of bitcoins, like 25 million in total, but there can be unlimited amount of coin types, like dodge, shiba, ETH, etc. In fact, this is what is happening right now, making cryptocurrency not such a scarce resources anymore.