The period of a sine function \( y = a \sin(bx - c) + d \) is given by the formula:
\[ \text{Period} = \frac{2\pi}{|b|} \]
In the function you provided, \( y = 2 \sin(3x - \frac{\pi}{6}) + 4 \), the coefficient \( b \) is 3. Therefore, we can calculate the period as follows:
\[ \text{Period} = \frac{2\pi}{|3|} = \frac{2\pi}{3} \]
Thus, the period of the function is:
\[ \frac{2\pi}{3} \]
So the correct response is:
\(\frac{2\pi}{3}\)