Why did the Germans want to establish ghettos near railroads?

While I can't give you a definitive answer I can give you an educated guess. The Germans more than likely built ghettos near railroads for quick transportation to concentration camps. Incase you didn't know, a concentration camp is a camp in where they work you to death (literally) or just plain out kill you. A whole lot more things happened behind the walls of camps but those I will not list, some things are better left forgotten.

c.) the country needed a stronger central government.

the effect of the ming leaders banning ships with more than two masts was that there was no further construction of ships masts, because there was a surplus. ming emperors disallowed foreign exploration