Explanation:

- Option 1: 2008: This is the correct answer. The National Payments Corporation of India (NPCI) was incorporated in 2008. It was established to create a robust payment and settlement infrastructure in India.

- Option 2: 2014: This is not the correct answer. Significant events happened later, but NPCI was already operational before 2014.

- Option 3: 2015: This is not correct. By 2015, NPCI had already achieved several milestones.

- Option 4: 2012: This is incorrect as well. By this time, NPCI was already functioning for a few years.

- Option 5: 2006: This is incorrect. NPCI was conceptualized in 2006, but formally incorporated later.