The correct answer is a. crop prices went down.
Simple as that. When the prices fell down, people could produce more for the same amount of money as earlier, which led to a boom.
Production of more food--the system allowed for more food to be produced which fed the workers in an industrial economy.
The 'four-field system' rotates crops between the 4 fields no longer needing to keep one empty because one of the crops would replenish the field with nutrients while the others take nutrients away from the fields. <span />
he surprised the enemy hhhhhh
This is Hemingway's belief that issues should be dealt with stoically and heroically. This can be seen in The Old Man and the Sea in the way the man never gives up and fights the Fish with all that he's got.
Hope it helps! :-)