Here Are Four Statements Describing Group Dynamics

Here are four statements describing group dynamics.Which of them is NOT an expression of groupthink?

A) Group members quickly settle on a position and then they treat other possibilities as oppositional.
B) Group members encourage each other to see the issue from only one point of view.
C) Group members treat reaching consensus as more important than encouraging everyone to speak up openly.
D) The group seeks diverse members and ends up being unable to reach a consensus.