All of the following were part of Carranza's strategy for controlling the U.S.-Mexican border except:

The strategy employed by Carranza regarding control of the U.S.-Mexican border revolved around formal regulations and policies aimed at managing immigration and foreign business interests. One notable aspect of this strategy was the implementation of increased taxes to restrict foreign business, which reflects a desire to prioritize Mexican businesses and exert economic control. Additionally, requiring immigrants to have written contracts before entering the country aligns with efforts to regulate the flow of individuals across the border legally.

Creating a U.S.-Mexican border patrol also underscores the formal mechanisms instituted to monitor and control immigration, as well as to maintain security along the border, which was a part of the broader control approach taken during this period.

The option that was not part of Carranza's strategy is linked to making border crossing unsafe and inhumane. While there were undoubtedly harsh realities associated with border crossings, Carranza's government focused more on establishing legal frameworks and regulatory measures rather than creating an unsafe environment as a means of deterrence. Therefore, this option does not accurately reflect Carranza's strategies.