Diversification, my friend, is the keyword. I would suggest you have investments in all three of them. So the question should rather be what should be your allocation to each of these instead of asking which is better.
If you are kind of investor who understands businesses, P&Ls, BLs OR technical charts etc your major chunk should be in Stocks.
Else it should be in actively-managed MFs.
Nevertheless, you can have a minor part of your investment in ETF (tracking indexes). Though, it beats me why one would invest in index when many of the popular actively-managed funds beat index comfortably.