Which of the Following Illustrates the Operation of "Groupthink

Which of the following illustrates the operation of "groupthink"?

A) A group leader makes a decision without consulting anyone, and the decision turns out to be a bad one.
B) A group gathers lots of information and makes a good policy recommendation.
C) A group seeks opinion differences and is unable to come up with any policy recommendation at all.
D) A group seeks consensus and discourages members from speaking freely, resulting in the group making a poor decision.