The answer to this question is letter c
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 think that maybe people are saying different answers because there might have been many such laws. I will mention one example: the Diversity Visa Immigration: it means that people from Eastern Europe have a higher change of obtaining a visa due to a smaller population in the US than the western European Countries.
Answer:
it shows how violent guns can be and especially if they get to the wrong people.