William Howard Taft leveraged American economic influence to tackle the problem of Latin America's debts to European nations primarily through the approach outlined in option C: He paid off the Latin American debts to European countries, so they were in debt to the U.S. instead.
This strategy was part of his "Dollar Diplomacy," which aimed to promote American financial interests abroad while simultaneously stabilizing countries in Latin America, ultimately allowing the U.S. to exert more influence in the region. By ensuring that the debts were paid to American banks and investors rather than European creditors, Taft sought to prevent European intervention in Latin American affairs.