The passage suggests that in 1968 Henry Cisneros most likely believed that:
Many Mexican American would respond positively to the example of Benito Juarez
If we look at the lines “Like European ethnic groups in the nineteenth-century United States, late-twentieth-century Mexican American leaders combined ethnic with contemporary civic symbols. In 1968, Henry Cisneros, then mayor of San Antonio, Texas, cited Mexican leader Benito Juarez as a model for Mexican Americans in their fight for contemporary civil rights”, it is evident that Henry Cisneros cited Benito Juarez as a model because he believed that many Mexican Americans would respond positively to his example. This is the most obvious reason behind citing any example. Therefore, answer option (a) is the most appropriate answer choice.