Answer:
B the diary of a woman crossing the prairie in a covered wagon during the 1800s
Step-by-step explanation:
The BEST illustration of a primary research source is the diary of a woman crossing the prairie in a covered wagon during the 1800s.
This is because, a primary source gives a first-hand information about an event as it is old by the person who witnessed it.
This is opposite to secondary information where the person giving the information does not have first-hand experience about what he's talking about.