C. 8.1% Explanation: The Public Provident Fund is a savings-cum-tax-saving instrument in India, introduced by the National Savings Institute of the Ministry of Finance in 1968.The aim of the scheme is to mobilize small savings by offering an investment with reasonable returns combined with income tax benefits. The current interest rate effective from 1 April 2016 is 8.1% Per Annum‘ (compounded annually).