How did medieval life and the feudal system break down? (select all that apply)

trade brought wealth and job opportunities to newly created cities.
kings had cities built to give serfs a place to live.
middle-class merchants who made a good living questioned the authoriy of landholders.
the crusades fought for the freedom of serfs and the manorialism way of living. factories employed those who would have been living on manors or under a king.

The feudalism system was kind of like conquering everything as your own(take the Japanese civil war for example) the decline of this lead to:
1.newer trade routes brought more wealth and job opportunities.
2. the serfs or peasants weren't being respected enough by the king and the crusader knights fought for their freedom.
3. peasants had a right to own land and prevent any merchants from taking it.

your answers should be the first one and the last one.