The nineteenth-century humanitarians who advocated kind treatment of the Indians a understood the value of the Indians' religious and cultural practices. b had no more respect for traditional Indian culture than those who sought to exterminate them. c None of these choices are correct. d advocated improving the reservation system. e opposed passage of the Dawes Act.

Option A,  Understood the value of the Indians' religious and cultural practices

Explanation:

By the end of 19th century, the humanitarians who advocated kind treatment of the Indians  basically understood the importance and strength of the Indian culture. Following this realization, several reforms were passed  to promote the private ownership of land to Indians and also provided an incentive to work thereby saved the population from continued decline.

hence, option A is correct

i believe that d is the right answer