It is universal rules, that higher the risk the higher would be returns. While RD is safe, the return on RD is very limited near to nil.
In my view, Mutual Fund is more suitable for higher returns. Although it has risk, but it has not the risk to the extent of that one which exist in Stock market. As the invested money in Mutual Fund is diversified in various stocks, so, in the case of the fall of market it doesn't affect the Mutual Fund, as it affect to the equity invested directly in Mutual Fund.
I would advise you to go for Mutual fund if you want to earn handsome money from your cash. In case, if you would like to save your money and not interested in earning out of it, you may opt for RD, which is almost safe.
Inspiring Quote: “A journey of a thousand miles begins with a single step" Lao-tsu
Mohammed Abuhuraira Akrami,