Introduction of the Brown Tree Snake on Guam Coincided with the Disappearance

Introduction of the brown tree snake on Guam coincided with the disappearance of birds and small reptiles on the island.Which of the following lead to this decline?

A) Competition for food with the snakes.
B) Predation by the snakes.
C) A side effect of poisons used to kill the snakes.
D) Competition for nesting sites with the snakes.
E) Habitat destruction that happened at the same time the snakes were introduced.