The radius of circle, the period of revolution, initial position and sense of revolution are indicated in the figure.

$y$-projection of the radius vector of rotating particle $P$ is

• A

  $y\left(t\right)=-3\cos 2\pi t,$ where $y$ in $\mathrm{m}$
• B

  $y\left(t\right)=4\sin \left(\frac{\pi t}{2}\right)$, where $y$ in $\mathrm{m}$
• C

  $y\left(t\right)=3\cos \left(\frac{3\pi t}{2}\right)$, where $y$ in $\mathrm{m}$
• Correct answer
  D

  $y\left(t\right)=3\cos \left(\frac{\pi t}{2}\right)$, where $y$ in $\mathrm{m}$

Hence, the correct answer is option: 'D'.