In the sentence “Who knows what other tricks the rainforest might have up its leaves?” (L 35 - 36) the author means that… A) nobody will ever know...

In the sentence “Who knows what other tricks the rainforest might have up its leaves?” (L 35 - 36) the author means that…
A) nobody will ever know how to decipher the enigmas of the rainforest.
B) There must be a way of learning more about the rainforest puzzles.
C) People doubt whether rainforest plants hide other mysteries.
D) It is impossible to find out all the applications of tree leaves.
E) It is possible that forest plants bring us additional surprises.