Option A i.e Pollution made in one country might contaminate the ground, water and air of other countries is the correct answer.
Toady is a global world and the challenges whether political, soio-economical or environmental in one country affects the other. As we know water and air have no real boundaries. The air and water of one country flows to the other. So pollution in one country contaminate the air and water in another country. That is why countries need to work together to mitigate the environmental damage.
