To analyze how the graph of the function \( f(x) = \sin \left(x - \frac{\pi}{6}\right) \) differs from the graph of \( \sin x \), we should look at the transformation applied to \( x \).
The function \( \sin(x - c) \) represents a horizontal shift of the sine function. Specifically:
- If \( c \) is positive, the graph shifts to the right by \( c \) units.
- If \( c \) is negative, the graph shifts to the left by \( |c| \) units.
In your case, you have \( c = \frac{\pi}{6} \) which is positive. Therefore, the graph of \( f(x) = \sin \left(x - \frac{\pi}{6}\right) \) is shifted to the right by \( \frac{\pi}{6} \) units.
Thus, the correct option is:
D. It shifts the graph of \(\sin x\) to the right by \(\frac{\pi}{6}\) units.