A country is said to be in balance-of-trade equilibrium when _____.

A、 it has the potential to produce all goods that its residents want without engaging in foreign trade
B、 the income its residents earn from exports is equal to the money its residents pay for imports
C、 the country import all goods that its residents want by engaging in foreign trade
D、 it has the potential to balance the production and procurement of the basic amenities that it needs