Suppose There Are Only Two Countries in the World, Countries

Suppose there are only two countries in the world, countries A and B. If the currency of country A appreciates, the currency of country B

A) must appreciate.
B) can appreciate relative to other countries.
C) may appreciate or depreciate, depending on the elasticity of demand for the exports of country A.
D) must depreciate.
E) may appreciate or depreciate, depending on the volume of trade between the two countries.