The answer is A, not B.
Corporations were very large because they employed many people on a very low wage.
The crusades were created by western European Christians after centuries of Muslim wars of expansion. To stop the expansion of Muslim states they had to reclaim christianity and the holy land in the middle east.
Im not sure exactly what your looking for but it may be something on the lines of: Historians base interpretations of past events on first hand sources which consist of diaries and writing or recordings of people who were at the event. A long with other sources such as newspapers.
