Send help :000 I suck at earth science

Which of these statements is the best reason for countries to work together to address environmental issues? a. environmental damage is caused mainly by developing countries that need to work together.b. pollution made in one country tends to stay in that country and harm only that country's residents.c. pollution made in one country might contaminate the ground, water, and air of other countries.d. international treaties are largely ineffective because developing countries lack the resources to enforce them.