Given the function $y=\sin (x-3\pi )$, identify the amplitude, period, and phase shift from the options below. Then, sketch its graph by considering only one period.

• A. $\text{Amplitude}=1,\text{ Period}=2\pi ,\text{ Phase shift}=-3\pi$
• B. $\text{Amplitude}=1,\text{ Period}=2\pi ,\text{ Phase shift}=3\pi$
• C. $\text{Amplitude}=3,\text{ Period}=2\pi ,\text{ Phase shift}=-3\pi$
• D. $\text{Amplitude}=3,\text{ Period}=\pi ,\text{ Phase shift}=3\pi$