The SEC recently postponed the approval of five cryptocurrency ETFs, and this decision isn't particularly surprising. The SEC has always been known for its caution, especially when it comes to volatile assets like altcoins, and their attitude has been one of careful consideration. After all, they are more concerned that the entire cryptocurrency market is not stable enough, and the regulatory framework has not fully kept pace.

However, if there is an ETF that is most likely to be approved, I believe it would be one focused on Solana (SOL). Why? First, Solana's technology has developed rapidly in recent years, with its high throughput and low transaction costs making it stand out in the market, especially in the decentralized finance (DeFi) and NFT sectors where it has strong use cases. Secondly, Solana's ecosystem is continuously expanding, with an influx of various projects and developers making it more 'reliable' than many other altcoins. Compared to some other cryptocurrencies, Solana's stability and innovation may be more appealing to the SEC.