Which Statement About the Study of the Invasive Klamath Weed

Which statement about the study of the invasive Klamath weed and a leaf-feeding beetle is true?

A) Plant populations cannot be reduced through herbivory.
B) A leaf-feeding beetle reduced the density of an invasive weed.
C) Both Klamath and the Chrysolina beetle are invasive.
D) Chrysolina beetle density remained indefinitely high after the decline in Klamath weed population.