Which was the main cause of the great migration to the united states in the late 1800s?

The discovery of America led to a great  power struggle for control of the new lands primarily between the three most powerful countries in Western Europe at the time: Spain, England, France. These European countries financed the voyages of the early explorers for many reasons. To increase their lands and build great European Empires and to increase the wealth of the 'Mother Country' by exploiting the natural resources of the new lands - the search began for gold, silver and spices. To increase opportunities for trade and to spread the Christian religion. That is what I managed to find online. Hope, it will help you somehow. And if you need the help to structure it all, please, go to the professional service as Marvelous essay service and let them do this job for you. 

i would say your answer is a)

sorry if im wrong

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.