A simple pendulum of length `L` has been set up inside a railway wagon sliding down a frictionless inclined plane of inclination `theta` with the horizontal. Its period of oscullation as recorded by an observer inside wagon is
A. `2pi sqrt((L)/(g cos theta))`
B. `2pi sqrt((L)/(g))`
C. `2pi sqrt((L)/(g Sin theta))`
D. `2pi sqrt((Lcos theta)/(g))`
