The correct answer is: C. 1972
The Special Inquiry Agency (SIA) was established in 1968 by the Government of Andhra Pradesh to investigate corruption cases. In 1972, the SIA was renamed the State Vigilance Bureau (SVB). The SVB is responsible for investigating corruption cases involving government employees, public servants, and politicians.
Option A: 1980 is incorrect because the SIA was renamed the SVB in 1972, not 1980.
Option B: 1990 is incorrect because the SIA was renamed the SVB in 1972, not 1990.
Option D: 1978 is incorrect because the SIA was renamed the SVB in 1972, not 1978.