Read the following excerpt from an intercalary chapter in the grapes of wrath in which a tractor driver discusses the future:

"times are changing, mister, don't you know? can't make a living on the land unless you've got two, five, ten thousand acres and a tractor. crop land isn't for little guys like us any more. you don't kick up a howl because you can't make fords, or because you're not the telephone company. well, crops are like that now. nothing to do about it. you try to get three dollars a day someplace. that's the only way."

by including this intercalary chapter, what effect is steinbeck most likely attempting to achieve?

a: breaking from the narrative flow of the novel to advance his purpose and perspective on crop rotation
b: providing commentary, separate from the narrative, which illustrates individual experiences during the great depression
c: creating a secondary narrative that runs parallel to the primary narrative but uses different characters and plot
d: giving readers a better understanding of the background of changes in communication and transportation at the time