Now that digital currency is becoming more and more popular in the whole world, there are lots of altcoins that exist in the market aside from Bitcoin. In your own opinion, what is/are the altcoin/s that will also be popular aside from Bitcoin and why did you say so?
Litecoin, because Bitcoin will not get segwit anytime soon, so as fees go higher in Bitcoin, people will look for alternatives to make payments, and Litecoin is the ideal alternative because it will have segwit and lighting networks backed by the Bitcoin Core's solid code.
Litecoin has always been there with bitcoin, it was overshadowed by bitcoin but it is a great coin on its own. I wouldn't be surprised to see litecoin take over bitcoin's throne, but that probably won't happen. But with segwit coming to litecoin it certainly gain some popularity.