Imagine the U.S. were to move to eliminate most import tariffs for manufactured goods from all its major trading partners. In return, those trading partners eliminate most import tariffs for manufactured goods made in the USA. How would this likely affect industry-level aggregate productivity in manufacturing industries in the USA? 

 a) Industry-level productivity would increase, especially for industries whose products were subject to the highest import tariffs before the change in policy. 

b) Industry-level productivity would decrease, especially for industries whose products were subject to the lowest import tariffs before the change in policy. 

c) Industry-level productivity would decrease, especially for industries whose products were subject to the highest import tariffs before the change in policy. 

d) Industry-level productivity would increase, especially for industries whose products were subject to the lowest import tariffs before the change in policy.