To simplify the expression \( \frac{1}{3}(9x - 5) \), you distribute \( \frac{1}{3} \) to both terms inside the parentheses:
\[ \frac{1}{3} \cdot 9x - \frac{1}{3} \cdot 5 = 3x - \frac{5}{3} \]
Therefore, the simplified expression is:
\[ 3x - \frac{5}{3} \]
None of the given choices match exactly; however, if we consider the format "3x - 5/3", this would refer to the same expression. Hence, the closest correct option would be:
3x - 5/3