FDs seem to be the most popular and risk free option. But with interest at about ~6.5%, they are barely beating inflation.
I'd do this for the next 2years atleast till a non-bjp, non-corrupt, non-stupid govt, non-lawyer FM comes in and takes things in correct direction. MF etc are subject to significant risk. Do not invest until you read up a lot and check out their returns for last 3-5years.
If there is enough surplus, one can also invest some amount in PPF as there is no upper limit on age.