Answer:
D. heavy lifting done by teams of men.
Step-by-step explanation:
George Milton and Lennie Small are characters in "Of Mice and Men" novel written by John Ernst Steinback Jr. George and Lennie are ranch workers who often move from one place to another during the Great Depression. Their migration was caused by the fact that they wanted to find several job opportunities in order to alleviate their situations. They also wanted to purchase their own land and settle down.
"To buck barley" in the statement above means "heavy lifting done by teams of men." In the story, George and Lennie would buck barley by throwing large bags of grain on a truck. Thus, they lifted the heavy bags of grains together in order to finish their task.
Thus, this explains the answer.