How did some of the popes demonstrate control in rome ?

The popes used religious influence to persuade people into believing that they should esteem to their God, and since the Pope was a in a hierarchy of religious figures they assumed a lead of being a political leader since he will place everyone on the right path of righteous rectitude. 

C, because he has a direct link and profit from the trade. the fastest way by boat to transport those goods is via the panama canal.