Given the function $y=\sin\left(x-3\pi\right)$, 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. $\text{Amplitude}=3,~\text{Period}=\pi,~\text{Phase shift}=3\pi$