What method of business combination is formed when several independent companies come together and agree to not compete by setting prices collectively.

The correct answer is b

In 911, a group of vikings lead by rollo besieged paris and chartres. after a victory near chartres on 26 august, charles decided to negotiate with rollo. the talks were led by hervé, the archbishop of reims. this resulted in the treaty of saint-clair-sur-epte, which granted rollo and his soldiers all the land between the river epte and the sea. it also granted him brittany, "for his livelihood". at the time, brittany was an independent land which france had not been able to conquer. in exchange, rollo promised the king his loyalty and military assistance when needed. also rollo also agreed to be baptised and to marry gisela, the king's daughter. the territory given rollo is about the same as upper normandy. this would grow to become normandy under rollo's descendants. - wikepedia

Because it changed the way poeple lived back then