As an indication that an air compressor air intake filter needs to be replaced or cleaned, what statement is true?

Correct Answer: Option D — For a given air demand, the compressor would run for longer periods and the air intake pressure as measured between the filter and the compressor inlet would be more negative than with a clean filter.

A clogged intake filter restricts airflow, causing a greater pressure drop across the filter element. This results in a more negative pressure at the compressor inlet. Because the compressor is moving less air mass per stroke, it must run for longer periods to satisfy the system's total air demand.