During the 1850s to 1950s, the primary focus of the public health effort in the united states was to

they were unable to pay their debts

the east coast has nothing to do with the dust bowl, the dust bowl killed a full year's worth of crops in seconds, and with the dust on the land, the land would be worthless.   furthermore the farmers couldn't  get  out of their houses due to the dust so when the bank came to collect money, farmers couldn't  pay it

c. troops marched forward in close formation against newer, more accurate weapons