As the depends how much profits and timing you want to hold! If you want short time then you can buy ethereum. But if you will keep hold very long time then you should buy bitcoin. Source like it will be invest then you will get green market. Although there are many top altcoins im the crypto market so you should take more coin name from cmc.
Ethereum is one of the good altcoin one can think of investing, it had good market value and it is reliable to invest than other altcoins. Another altcoins I can consider to invest is the BNB, this are the altcoins I can go for without being worried so much about it because they have good market value and are reliable to invest. Instead of considering altcoins for investment that one can't really tell if is good for investing in it.