During the Era of the Gold Standard, the Price of Gold

During the era of the gold standard, the price of gold in England:

A) was always equal to the price of gold in the United States.
B) was always a little higher than the price of gold in the United States, but it could not be higher by more than the cost of transporting gold from the United States to England.
C) was always a little lower than the price of gold in the United States, but it could not be lower than the cost of transporting gold from England to the United States.
D) could be higher or lower than the price of gold in the United States, but not by more than the cost of transporting gold between the two countries.