What was not a key contribution of china?

a. gunpowder
b. porcelain
c. compass
d. wheel

What does a most-favored-nation (mfn) status mean? a country pays the same tariffs as those paid by all mfn countries. a country has a special exemption from all tariffs in the united states. a country has special licensing agreements with u.s. corporations. a country is exempt from product standards that make it expensive for goods to be imported.