I'll respond with an ironic answer: USDC. Why? I think we are heading into a bear market and, if this is the case, cash on the sidelines will be very useful to scoop up much cheaper altcoins. History proves that bear markets are when the real money is made, as investors then patiently wait for the bull market to arrive.
But even if we buy USDC then also we have to wait for the right time to invest in the crypto that we want to buy, if not then we will be holding a stable currency only which would be a big mistake. For me, the price has already fallen much and now it is a decent time to buy any top crypto currency like btc or ETH, even BNB is a pretty good buy considering most of the new projects are coming on the binance smart chain instead of ethereum smart chain.