The ku klux klan declined in popularity during the later years of reconstruction because southerners began to blame the klan for victory of a. the republican party in congressional elections. b. continued military occupation of the southern states. c. defeat of the confederate forces in the civil war. d. successful passage of the reconstruction amendments.

B. continued military occupation of the southern states.

Explanation:

The Ku Klux Klan is a white supremacist organization, founded in 1866 in Tennessee and expanded to almost every southern state by 1870, it became one of the main powers against the republican party reconstruction and the new policies they were trying to pass, through terrorism attacks and cross burnings, they were terrifying the south and that´s why it eventually had to be military occupied.

the answer would be logic.