Final answer:
Clinton's impeachment trial was not a cause of division during the 1960s and 1970s, as it occurred in the 1990s. The division during the 60s and 70s was due to the Vietnam War, high-profile assassinations, and the Watergate Scandal.
Step-by-step explanation:
The division in America during the 1960s and 1970s was the result of several concurrent events which deeply affected the nation's psyche and politics. Option d, Clinton's impeachment trial, was not a reason for division during the 60s and 70s; it's an event that occurred much later, in the late 1990s. During the 60s and 70s, the country was torn by the Vietnam War, which led to massive anti-war demonstrations, public disenchantment following the Pentagon Papers, and eventually the end of the conflict with a withdrawal of U.S. troops. The assassinations of high-profile leaders like President Kennedy and Martin Luther King Jr. were significant shocks that contributed to societal divisions. The Watergate Scandal further eroded trust in the government as it revealed an abuse of power at the highest political levels. All these issues represent the tumultuous nature of the era and underscore the collective challenges Americans faced.