Tanks could be used to open a hole in enemy lines, but the burnt of the fighting must be done by infantry units. Early tanks for the allies had limited transverse movement for the turret, because their primary purpose was to serve as a gun platform for the infantry units coming behind them.
I would go with answer
B: They both relied on each other for goods and services.
Harper's Ferry was a ship with a large arsenal.
Serfs may eventually work their way to freedom (usually not), if you know the term tenant farmers, individuals who work on a property with some believe that eventually they may pay their debts off and become a freeman. An enslaved person, will never believe that they will eventually become free.
-My opinion anyway (probably wrong) but worth a try.
1 Germany lost land, the Ottoman Empire was dissolved and Russia lost some land. 2 Ottoman Empire and Germany. Well the Ottoman empire was destroyed and Germany was forced to give it up.
