“a nigerian tariff on car imports aimed at boosting local production has reduced the number of vehicles brought into the country this year by a quarter and fuelled smuggling from neighboring benin, the ports authority said. car imports fell to 70,453 units in the first 10 months of this year (2017), a 26.8 percent reduction on the same period of 2016, nigerian ports authority (npa) figures showed. the government imposed a 70 percent tariff on imported vehicles in december 2015 as part of attempts by president muhammadu buhari to stimulate local production.” - from “nigeria tariff causes car imports to fall, fuels smuggling - ports authority,” reuters, december 15, 2017 the main topic of this article centers around a) trade barriers. b) specialization. c) embargoes and quotas. d) environmental regulations.