How do the photographs contribute to the reader’s understanding of the passage?
A.They show the opportunity for increased productivity after the switch from the single, horse-drawn plow to the multi-disc, tractor-pulled plow.
B.They show the types of Great Plains landscapes where farmers planted cash crops such as wheat.
C.They contrast the number of men needed when using horses with the number of men needed for tractors
D.They contrast the simple and easily maintained horse-drawn plow with the complicated and expensive tractor-pulled plow.