Question

One reason why Japan has enjoyed economic success is because its workers have a strong _________. tariff work ethic Osaka trade surplus

Answer 1

 I assume that these are the options.
 the first option, tariff, is a form of tax.
 the second option, work ethic, is indeed something the workers can do to improve the economy so this is the correct answer
 
Osaka is a city and trade surplus would be more  an effect than it cause for good economy