How does the Nelson Denny test accommodate different skill levels?

The correct answer highlights how the Nelson Denny test is designed to assess a range of reading comprehension skills by incorporating passages of varying complexity. This approach allows for a more comprehensive evaluation of a test taker's abilities. By including a spectrum of text difficulties, the test can effectively differentiate between various skill levels, providing a nuanced understanding of the individual's reading capabilities. This feature encourages test takers to engage with materials that match their proficiency and challenges them appropriately, ultimately presenting a more accurate portrayal of their reading strengths and areas for improvement.

The other options suggest methods that would not serve the test's purpose effectively. Simplifying all passages would eliminate the opportunity to assess higher-level comprehension skills, while excluding difficult questions would restrict the range of skills being tested. Allowing infinite time would not reflect the real-world situations where time management is essential, thereby diminishing the test's validity as a measure of reading comprehension under time constraints.