To simplify \( \frac{1}{3}(9x - 5) \), we distribute \( \frac{1}{3} \) to both terms inside the parentheses:
\[ \frac{1}{3}(9x) - \frac{1}{3}(5) \]
Calculating each term gives:
\[ 3x - \frac{5}{3} \]
Therefore, the simplified expression is:
3x - 5/3
Thus, the correct choice among the responses given is:
3 x minus 5 thirds.