What was the effect of the ming emperors disallowed foreign exploration?

Simply to create a scarcity of the goods involved and a 'black market'.

The intent: To exclude foreign ideas & influences was only partly successful.

the correct answer is “opportunity cost”. opportunity cost is what a company misses out because it decided in one option over another one. in this case, the company decided to invest in building a factory so it gave up another possible benefit or profit in order to achieve success with the factory.  

trade-off is not the correct answer since it is a situation in which you accept losing something in return for benefits in other areas.

and finally, consequence is a general term used to accept what it comes when you make a decision. it can be a positive or negative consequence depending if the decision you took was the correct one.  

the answer should be a. the sui empire, the tang empire extended from korea in the west to manchuria in the east.