To represent the statement "The sum of 4.5 and one-third of a number is equal to at most 38.9," we can write it as an inequality.
Let \( n \) be the number. The sum of 4.5 and one-third of \( n \) can be expressed as:
\[ \frac{1}{3}n + 4.5 \]
The phrase "equal to at most" indicates that this expression can be less than or equal to 38.9. Therefore, the appropriate inequality is:
\[ \frac{1}{3}n + 4.5 \leq 38.9 \]
So, the correct response from your options is:
\[ \frac{1}{3}n + 4.5 \leq 38.9, \text{ where } n \text{ is equal to the number.} \]