QUESTION $21(4$ Marks$)$ In the United States, tariff revenues in fiscal year $2023$ were slightly more than USD$$80$ billion, while total U$.$S government revenues for that year were USD $$4\mathrm{.}439$ trillion. The global proliferation of free agreements since World War II has substantially lowered tariff rates, and in turn lowered tariff revenue in wealthy countries, though a number of developing countries still rely on tariffs for a substantial proportion of government revenues. $,$ which of the following BEST describes the impact of tariffs based on the data from fiscal year $2023?$ a$)$ Tariff revenues accounted for a significant proportion of the U$.$S$.$ government$$s total revenue in $2023.$ b$)$ Tariffs remain a key source of government revenue for the U$.$S$.$ due to ongoing trade wars. c$)$ Tariff revenues were a small fraction of total U$.$S$.$ government revenues in $2023,$ highlighting the shift towards lower tariffs in global trade. d$)$ Developing countries rely on tariffs as the primary source of government revenue, despite the global trend of reducing tariff rates.