Answer:
Diary or personal account that was written during the time of the event, etc.
Explanation:
Without a set of options in front of me, my best guess would be something along the lines of my above answer. Primary sources are typically diaries, legal codes, and other firsthand accounts/sources of information. They typically provide the most accurate account of the event that occurred because they have not been interpreted further by any other people.
The stock market crashed...
His invention allowed people to build factories far from rivers
The Church did not know any other way then following the Bible, causing an unwanted and unfamiliar change to their environment