Final answer:
Jewish people and other persecuted groups during the Holocaust were predominantly relocated to concentration camps using trains, which took them to extermination sites where many were killed upon arrival. Hence, the correct answer is option B.
Step-by-step explanation:
Most Jewish people, along with other persecuted groups, were forcibly relocated to concentration camps by means of trains. During the Holocaust, beginning with the German invasion of Poland in 1939 and the subsequent establishment of ghettos, Jews were subjected to crowded living conditions and forced labor.
In early 1942, extermination camps in Eastern Europe were opened, and Jews were transported primarily through railroad cattle-cars. Upon arrival, many were sent directly to gas chambers disguised as showers. An estimated 6 million European Jews were murdered in these camps, alongside millions of members of other minority groups.