
Passage: During the Industrial Revolution, two plant diseases disappeared in heavily polluted British industrial cities: black spot, which infects roses, and tar spot, which infects sycamore. Biologists believe that air pollution may have eliminated these two diseases.
Question: If which of the following statements is true, it will most strongly support the above argument?
A. A.Black spot disease and tar spot disease recur when urban air pollution is reduced
B. B.It is not clear whether the effects of air pollution on many plant species are beneficial or harmful
C. C.There are ways to prevent infection with black spot and tar spot, but once infection is difficult to eradicate
D. D.Some plants can produce strong resistance to air pollution
Answer: