问题：
[单选] The purpose of a custom is to cut down imports in order to protect domestic industry and workers from foreign competition.A . tax
B . toll
C . fee
D . tariff
参考答案：D
参考解析：
【答案】D
【解析】tax“税，税款”；toll“服务费”；fee“费用”；tariff“关税”。
The purpose of a custom is to cut down
The purpose of a custom is to cut down imports in order to protect domestic industry and workers from foreign competition.
