Which of the following best describes the efficiency of dry scrubbers at removing

Which of the following best describes the efficiency of dry scrubbers at removing particles that are less than 2 micrometers in diameter? Dry scrubbers are less than 20% efficient at removing particles less than 1μm and increase to over 50% efficiency at removing particles between 1 and 2μm. A Dry scrubbers are between 50% and 90% efficient at removing particles less than 2μm, depending on the flow rate. B Dry scrubbers are between 5% and 40% efficient at removing particles less than 2μm in size. C Dry scrubbers are less than 10% efficient at removing particles less than 1μm in size.