Answer:
d. an antecedent boundary
Explanation:
An antecedent boundary is defined as a political boundary that is created before settlement and existed till the settlement.
The international border between East Germany and West Germany is known as Berlin wall, which is an antecedent boundary that was created to stop the large-scale emigration of people from East German to the West after get defeated in World War II.
Hence, the correct answer is "d. an antecedent boundary".
