Inflation -- a Comparative Study Amongst Different Modified Gravity
  Theories
  In the recent years, a host of modified gravity models have been proposed as
alternatives to the dark energy. A quantum theory of gravity also requires to
modify `General Theory of Relativity'. In the present article, we consider five
different modified theories of gravity, and compare inflationary parameters
with recent data sets released by two Planck collaboration teams. Our analysis
reveals that the scalar-tensor theory of gravity is the best alternative.
