If you could invest $ 1 million but only in one stock, what would it be?

If you had only one stock to invest $1Million today, which would it be?

You can only invest in one stock and It had to be held long term.

It has to be a monopoly or duopoly company.
The stock has to be other than the common stocks such as GOOGL,AMZN,AAPL.

I got a opportunity similar to this, I am not able to select the stock.
If your suggestion is actually helpful, I will share a certain percent of the gain made.