What was the major campaign issue in the election of 1928?

A major reason for Herbert Hoover’s landslide victory in the 1928 election was the prosperity of the 1920's. In the early 1920's there was a large economic boom and Herbert Hoover pledged to continue that. 

That the political parties were overpowering the others

they required less loading and unloading

explanation:

the shipping container improved shipping because it cut down on unloading time by three weeks, eliminated wasted space, and allowed ships to carry.

i believe the answer is c