Which book, authored by an American writer, highlighted injustices against Native Americans?

The correct choice is "A Century of Dishonor," authored by Helen Hunt Jackson. This influential book, published in 1881, specifically aimed to shed light on the injustices faced by Native Americans throughout U.S. history. Jackson's work combines historical accounts with her poignant commentary to bring awareness to the plight of Native Americans, particularly the broken treaties and the ongoing discrimination they faced from the federal government and society at large. Her advocacy played a significant role in galvanizing public sentiment towards the rights and acknowledgment of Native Americans.

While "Black Elk Speaks" is a pivotal text that recounts the experiences and spiritual life of a Lakota man, it is more focused on the cultural narrative rather than a direct critique of injustices. "Huckleberry Finn," written by Mark Twain, predominantly explores themes of racism and moral dilemmas but does not center on Native American issues specifically. "The Book of Native American Mythology" is a general work about myths and traditions rather than an examination of injustices. Thus, "A Century of Dishonor" stands out as the definitive work addressing the specific injustices encountered by Native Americans in American history.