Identify the correct statement.

a) Freer trade in environmental services actually lowers environmental quality, especially in the developing countries.

b) There is sufficient evidence to prove that free trade simply promotes production and consumption of products that tend to cause large amounts of pollution.

c) Environmentalists often fear that free trade permits production to be shifted to countries that have lax environmental standards.

d) It is not easy to find cases where government policies that limit or distort trade result in environmental damage.