Which type of group is most susceptible to groupthink?

A) groups that meet casually
B) tightly knit groups
C) groups containing only members of the same sex
D) groups that were randomly assigned to meet together.

Tightly knit groups are the most susceptible to groupthink because members are more likely to value group harmony over critical thinking and may feel pressure to conform to the group's norms and ideas. Casual groups, groups containing only members of the same sex, and randomly assigned groups are less likely to experience groupthink.