Which Is Not a Benefit of Using Lichen as an Indicator

Which is not a benefit of using lichen as an indicator of air quality over traditional methods?

A) Scientists essentially have a record of environmental pollutants spanning centuries stored in lichen specimens preserved in natural history museums.
B) Historical lichen samples can be used to analyze the effectiveness of past cleanup efforts and regulatory programs for controlling environmental pollutants.
C) The use of lichens as biological indicators of pollution/air quality does not require expensive equipment.
D) Lichens grow quickly and respond rapidly to changes in air quality, providing real-time updates to scientists regarding environmental conditions.
E) Maps of lichen growth and diversity can provide environmental biologists with an inexpensive tool for tracking the distribution of air pollutants and their effects around cities.