Final answer:
The sharp increase in votes for the Nazi Party from 1928 to 1930 was most likely due to the start of the Great Depression.
Step-by-step explanation:
The event that most likely accounted for the sharp increase in votes for the Nazi Party from 1928 to 1930 was the start of the Great Depression. The economic crisis caused by the Depression created a sense of fear and uncertainty among the German population, which made them more willing to support extremist political parties like the Nazis. The Nazi Party, under the leadership of Adolf Hitler, capitalized on the economic discontent and promised to restore economic stability and national pride.
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