Final answer:
Groupthink is influenced by the team pressure to conform, the illusion of unanimity among group members, and the false belief in the group's invulnerability, therefore the correct answer is 'd. all of the above'.
Step-by-step explanation:
The characteristics that make members susceptible to groupthink are diverse and interrelated.
- These include team pressure to conform, creating an environment where dissent is discouraged, and consensus is forced.
- Another characteristic is the illusion of unanimity, where members of the group falsely perceive that everyone agrees when in reality, some may not.
- A third characteristic is the illusion that the group is invulnerable, which leads to overconfidence and the belief that the group's decisions are incapable of error.
Therefore, the answer to the question of which group characteristics make members susceptible to groupthink is d. all of the above.