What is better tax saving investment option PPC or NSC?

The best part of PPF was return were tax free however money gets locked for 15 years. . Compared to PPF NSC had one advantage that money was locked for only 6 years but disadvantage was that returns were taxable. With the Effect of DTC on PPF the returns from PPF will be taxable on withdrawal. So now what is better PPF or NSC. Can anyone guide me some investment with guarantied return and tax exempt on returns in India?