What is the best investment option for a long term investment? I want my money to double in three years.?

Best of luck getting your money to double in 3 years (that's a might tall order).

A nice diversified portfolio of good stock mutual funds can average 12% a year. At that rate it would take about 6 years or so to double.

If you want to double your money faster, you'll need to be real lucky and/or get real speculative with your investments.

I hate to tell you, but 3 years is not a long term investment. In order for you to have the potential to double your investment in 3 years, you will need to do more speculative or higher risk investment. That means that you could also lose some of your investment because of the higher potential returns. Real estate can be a good investment as can some stocks. OTC stocks tend to be more volitile than blue chips. If you can find an area where there is development you stand a chance to make more money with real estate. I think you may need to consult with a financial advisor to help you reach your financial goals. There could be some limited partnerships who do real estate developments or other investments which could work for you.

3 years IS NOT LONG TERM. Try ten or more! ...and the stock market.