Short answer A <<<<<
It was intended to foster mutual trade relations between the three countries.
Only Trump and his ilk found that not to be true for them. There is a return to isolationism afoot. Not a good practice.
Answer:That is, cooler and more rigid outer portion. The lithosphere of the Earth comprises the crust and the uppermost mantle that forms the rigid and hard outer layer of the Earth. The lithosphere is sub-differentiated into tectonic plates.
