Germans fled to Minnesota for many reason, with D) because a large wave of Germans immigrated to the Midwest in the 19th century being one of them.
It happened to be that Minnesota Indian treaties offered a vast amount of valuable land to those who wanted it, and those people happened to be the Germans. Overtime, more Germans moved in order to escape a plethora of reasons, and found the Midwest to be a great pace.
I hope this helps! :)