The Silk Road did not only promote commodity exchange but also cultural. For example, Buddhism as one of the religions of the Kushan kingdom reached China. Together with merchant caravans, Buddhist monks went from India to Central Asia and China, preaching the new religion.
They believed that the Vietnam War was a mistake. By 1968, a majority of Americans believed that the Vietnam War was a mistake. The other choices given above are not related to what happened during 1968. Hope this answer helps.
