We Can Control Invasive Species by All but Which One

Multiple Choice

We can control invasive species by all but which one of the following ways?

A) Increase inspections of imported goods.
B) Create international laws forbidding the trade in invasive species.
C) Enact laws requiring cargo ships to empty their ballast water at sea.
D) Create chemicals to control existing invasive species and prevent new ones from establishing.
E) Increase research in natural methods to control invasive species.