The time period and the amplitude of a simple pendulum are 4 second and 0.20 metre respectively. If the displacement is 0.1 m at time t = 0, the equation of its displacement is represented by:

• A

  $\mathrm{y}=0.2 \sin (0.5\mathrm{\pi t})$

• B

  $\mathrm{y}=0.2 \sin (0.5\mathrm{\pi t}+\mathrm{\pi }/6)$

• C

  $\mathrm{y}=0.1 \sin \left(\mathrm{\pi t}+\mathrm{\pi }/6\right)$

• D

  $\mathrm{y}=0.1 \sin \left(0.5 \mathrm{\pi t}\right)$