The correct answer is B) Criticizing court-ordered busing of school children.
Nixon's southern strategy was focused on how to gain the support of white voters in the deep South. This strategy often had racial undertones. The goal of this strategy was to use this idea of racism as a means to gain support for his campaigns. The criticizing of integrated busing of school children was one way Nixon gained support, as he believed this should have been an issue decided on the state level.
