Which is the best altcoin to invest upon in current month of Feb and upcoming month of March?

There is no answer for that. Choices are very personal.
Personally, I have reduced my portfolio to 5 coins only, I got 60% on BTC and 10% in other 4 projects (QTUM, BNB, XMR & CCX)
My newest investment is Conceal $CCX. Cryptonote coin with deposits with interest on the blockchain. IMO privacy protected coins have loads of potential and Conceal is very exquisite. I am following the development and I am loving it. Have a look at it,
https://conceal.network/ &
https://github.com/TheCircleFoundationFor me nothing else but Bitcoin or Ethereum because beside of being profitable, both are safe to invest because of they have good technology which is its not easy to hack especially in bitcoin. If you're going to invest make sure it has potential, then review its past movement in the market so that it will help you if it has a chance to increase or possible to rise even more.