To calculate the probability of finding an error on the next page Denise reads, we can use the information provided about the errors found in the pages she has already read.
Denise found errors on 4 out of 250 pages. The probability \( P \) of finding an error on the next page can be calculated using the formula:
\[ P = \frac{\text{Number of errors}}{\text{Total pages read}} = \frac{4}{250} \]
Calculating this:
\[ P = \frac{4}{250} = 0.016 \]
To convert this probability into a percentage, we multiply by 100:
\[ P \times 100 = 0.016 \times 100 = 1.6% \]
Therefore, the probability that Denise finds an error on the next page she reads is C. 1.6%.