Where and by whom might french royal power be challenged after 1328?

The French royal power could be questioned because: after the death of Charles IV of France in 1328 there was no male heirs and that ended the main Capetian line. Under Salic law the crown could not pass through a woman (Philip IV's daughter was Isabella, whose son was Edward III of England), so the throne passed to Philip VI, son of Charles of Valois. This, in addition to a long-standing dispute over the rights to Gascony in the south of France, and the relationship between England and the Flemish cloth towns, led to the Hundred Years' War of 1337–1453. The following century was to see devastating warfare, peasant revolts (the English peasants' revolt of 1381 and the Jacquerie of 1358 in France) and the growth of nationalism in both countries.

true

coz they had the rank system in society according to the economic power of the people

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.