When Iraq invaded Iran that led the u.s to take action
Civil rights and Vietnam--SDS or Students for a Democratic Society fought for civil rights issues and protested against the Vietnam War.
SDS were mostly a youth movement using protests as a means to address the issues important to them. It was centered on college campuses and fought for civil rights for many marginalized groups. They also actively protested against the Vietnam War.
Almost certain it is B, Indian removal act.